diff --git a/res/css/structures/_LeftPanel.scss b/res/css/structures/_LeftPanel.scss
index 35d9f0e7da..899824bc57 100644
--- a/res/css/structures/_LeftPanel.scss
+++ b/res/css/structures/_LeftPanel.scss
@@ -23,6 +23,14 @@ limitations under the License.
     flex: 0 0 auto;
 }
 
+// TODO: Remove temporary indicator of new room list implementation.
+// This border is meant to visually distinguish between the two components when the
+// user has turned on the new room list implementation, at least until the designs
+// themselves give it away.
+.mx_LeftPanel2 .mx_LeftPanel {
+    border-left: 5px #e26dff solid;
+}
+
 .mx_LeftPanel_container.collapsed {
     min-width: unset;
     /* Collapsed LeftPanel 50px */
diff --git a/src/ContentMessages.tsx b/src/ContentMessages.tsx
index 249ad8381c..25445b1c74 100644
--- a/src/ContentMessages.tsx
+++ b/src/ContentMessages.tsx
@@ -31,6 +31,7 @@ import Spinner from "./components/views/elements/Spinner";
 
 // Polyfill for Canvas.toBlob API using Canvas.toDataURL
 import "blueimp-canvas-to-blob";
+import { Action } from "./dispatcher/actions";
 
 const MAX_WIDTH = 800;
 const MAX_HEIGHT = 600;
@@ -529,7 +530,7 @@ export default class ContentMessages {
         dis.dispatch({action: 'upload_started'});
 
         // Focus the composer view
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
 
         function onProgress(ev) {
             upload.total = ev.total;
diff --git a/src/components/structures/LeftPanel.js b/src/components/structures/LeftPanel.js
index a1b4f49c56..05cd97df2a 100644
--- a/src/components/structures/LeftPanel.js
+++ b/src/components/structures/LeftPanel.js
@@ -26,7 +26,7 @@ import * as VectorConferenceHandler from '../../VectorConferenceHandler';
 import SettingsStore from '../../settings/SettingsStore';
 import {_t} from "../../languageHandler";
 import Analytics from "../../Analytics";
-import RoomList2 from "../views/rooms/RoomList2";
+import {Action} from "../../dispatcher/actions";
 
 
 const LeftPanel = createReactClass({
@@ -198,7 +198,7 @@ const LeftPanel = createReactClass({
 
     onSearchCleared: function(source) {
         if (source === "keyboard") {
-            dis.dispatch({action: 'focus_composer'});
+            dis.fire(Action.FocusComposer);
         }
         this.setState({searchExpanded: false});
     },
@@ -274,28 +274,15 @@ const LeftPanel = createReactClass({
             breadcrumbs = (<RoomBreadcrumbs collapsed={this.props.collapsed} />);
         }
 
-        let roomList = null;
-        if (SettingsStore.isFeatureEnabled("feature_new_room_list")) {
-            roomList = <RoomList2
-                onKeyDown={this._onKeyDown}
-                resizeNotifier={this.props.resizeNotifier}
-                collapsed={this.props.collapsed}
-                searchFilter={this.state.searchFilter}
-                ref={this.collectRoomList}
-                onFocus={this._onFocus}
-                onBlur={this._onBlur}
-            />;
-        } else {
-            roomList = <RoomList
-                onKeyDown={this._onKeyDown}
-                onFocus={this._onFocus}
-                onBlur={this._onBlur}
-                ref={this.collectRoomList}
-                resizeNotifier={this.props.resizeNotifier}
-                collapsed={this.props.collapsed}
-                searchFilter={this.state.searchFilter}
-                ConferenceHandler={VectorConferenceHandler} />;
-        }
+        const roomList = <RoomList
+            onKeyDown={this._onKeyDown}
+            onFocus={this._onFocus}
+            onBlur={this._onBlur}
+            ref={this.collectRoomList}
+            resizeNotifier={this.props.resizeNotifier}
+            collapsed={this.props.collapsed}
+            searchFilter={this.state.searchFilter}
+            ConferenceHandler={VectorConferenceHandler} />;
 
         return (
             <div className={containerClasses}>
diff --git a/src/components/structures/LeftPanel2.tsx b/src/components/structures/LeftPanel2.tsx
new file mode 100644
index 0000000000..c9a4948539
--- /dev/null
+++ b/src/components/structures/LeftPanel2.tsx
@@ -0,0 +1,154 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import * as React from "react";
+import TagPanel from "./TagPanel";
+import classNames from "classnames";
+import dis from "../../dispatcher/dispatcher";
+import AccessibleButton from "../views/elements/AccessibleButton";
+import { _t } from "../../languageHandler";
+import SearchBox from "./SearchBox";
+import RoomList2 from "../views/rooms/RoomList2";
+import TopLeftMenuButton from "./TopLeftMenuButton";
+import { Action } from "../../dispatcher/actions";
+
+/*******************************************************************
+ *   CAUTION                                                       *
+ *******************************************************************
+ * This is a work in progress implementation and isn't complete or *
+ * even useful as a component. Please avoid using it until this    *
+ * warning disappears.                                             *
+ *******************************************************************/
+
+interface IProps {
+    // TODO: Support collapsed state
+}
+
+interface IState {
+    searchExpanded: boolean;
+    searchFilter: string; // TODO: Move search into room list?
+}
+
+export default class LeftPanel2 extends React.Component<IProps, IState> {
+    // TODO: Properly support TagPanel
+    // TODO: Properly support searching/filtering
+    // TODO: Properly support breadcrumbs
+    // TODO: Properly support TopLeftMenu (User Settings)
+    // TODO: a11y
+    // TODO: actually make this useful in general (match design proposals)
+    // TODO: Fadable support (is this still needed?)
+
+    constructor(props: IProps) {
+        super(props);
+
+        this.state = {
+            searchExpanded: false,
+            searchFilter: "",
+        };
+    }
+
+    private onSearch = (term: string): void => {
+        this.setState({searchFilter: term});
+    };
+
+    private onSearchCleared = (source: string): void => {
+        if (source === "keyboard") {
+            dis.fire(Action.FocusComposer);
+        }
+        this.setState({searchExpanded: false});
+    }
+
+    private onSearchFocus = (): void => {
+        this.setState({searchExpanded: true});
+    };
+
+    private onSearchBlur = (event: FocusEvent): void => {
+        const target = event.target as HTMLInputElement;
+        if (target.value.length === 0) {
+            this.setState({searchExpanded: false});
+        }
+    }
+
+    public render(): React.ReactNode {
+        const tagPanel = (
+            <div className="mx_LeftPanel_tagPanelContainer">
+                <TagPanel/>
+            </div>
+        );
+
+        const exploreButton = (
+            <div
+                className={classNames("mx_LeftPanel_explore", {"mx_LeftPanel_explore_hidden": this.state.searchExpanded})}>
+                <AccessibleButton onClick={() => dis.dispatch({action: 'view_room_directory'})}>
+                    {_t("Explore")}
+                </AccessibleButton>
+            </div>
+        );
+
+        const searchBox = (<SearchBox
+            className="mx_LeftPanel_filterRooms"
+            enableRoomSearchFocus={true}
+            blurredPlaceholder={_t('Filter')}
+            placeholder={_t('Filter rooms…')}
+            onKeyDown={() => {/*TODO*/}}
+            onSearch={this.onSearch}
+            onCleared={this.onSearchCleared}
+            onFocus={this.onSearchFocus}
+            onBlur={this.onSearchBlur}
+            collapsed={false}/>); // TODO: Collapsed support
+
+        // TODO: Improve props for RoomList2
+        const roomList = <RoomList2
+            onKeyDown={() => {/*TODO*/}}
+            resizeNotifier={null}
+            collapsed={false}
+            searchFilter={this.state.searchFilter}
+            onFocus={() => {/*TODO*/}}
+            onBlur={() => {/*TODO*/}}
+        />;
+
+        // TODO: Breadcrumbs
+        // TODO: Conference handling / calls
+
+        const containerClasses = classNames({
+            "mx_LeftPanel_container": true,
+            "mx_fadable": true,
+            "collapsed": false, // TODO: Collapsed support
+            "mx_LeftPanel_container_hasTagPanel": true, // TODO: TagPanel support
+            "mx_fadable_faded": false,
+            "mx_LeftPanel2": true, // TODO: Remove flag when RoomList2 ships (used as an indicator)
+        });
+
+        return (
+            <div className={containerClasses}>
+                {tagPanel}
+                <aside className="mx_LeftPanel dark-panel">
+                    <TopLeftMenuButton collapsed={false}/>
+                    <div
+                        className="mx_LeftPanel_exploreAndFilterRow"
+                        onKeyDown={() => {/*TODO*/}}
+                        onFocus={() => {/*TODO*/}}
+                        onBlur={() => {/*TODO*/}}
+                    >
+                        {exploreButton}
+                        {searchBox}
+                    </div>
+                    {roomList}
+                </aside>
+            </div>
+        );
+    }
+}
diff --git a/src/components/structures/LoggedInView.tsx b/src/components/structures/LoggedInView.tsx
index 7fcaadf7a5..0504e3a76a 100644
--- a/src/components/structures/LoggedInView.tsx
+++ b/src/components/structures/LoggedInView.tsx
@@ -51,6 +51,8 @@ import {
     showToast as showServerLimitToast,
     hideToast as hideServerLimitToast
 } from "../../toasts/ServerLimitToast";
+import { Action } from "../../dispatcher/actions";
+import LeftPanel2 from "./LeftPanel2";
 
 // We need to fetch each pinned message individually (if we don't already have it)
 // so each pinned message may trigger a request. Limit the number per room for sanity.
@@ -358,7 +360,7 @@ class LoggedInView extends React.PureComponent<IProps, IState> {
             // refocusing during a paste event will make the
             // paste end up in the newly focused element,
             // so dispatch synchronously before paste happens
-            dis.dispatch({action: 'focus_composer'}, true);
+            dis.fire(Action.FocusComposer, true);
         }
     };
 
@@ -508,7 +510,7 @@ class LoggedInView extends React.PureComponent<IProps, IState> {
 
             if (!isClickShortcut && ev.key !== Key.TAB && !canElementReceiveInput(ev.target)) {
                 // synchronous dispatch so we focus before key generates input
-                dis.dispatch({action: 'focus_composer'}, true);
+                dis.fire(Action.FocusComposer, true);
                 ev.stopPropagation();
                 // we should *not* preventDefault() here as
                 // that would prevent typing in the now-focussed composer
@@ -667,6 +669,20 @@ class LoggedInView extends React.PureComponent<IProps, IState> {
             bodyClasses += ' mx_MatrixChat_useCompactLayout';
         }
 
+        let leftPanel = (
+            <LeftPanel
+                resizeNotifier={this.props.resizeNotifier}
+                collapsed={this.props.collapseLhs || false}
+                disabled={this.props.leftDisabled}
+            />
+        );
+        if (SettingsStore.isFeatureEnabled("feature_new_room_list")) {
+            // TODO: Supply props like collapsed and disabled to LeftPanel2
+            leftPanel = (
+                <LeftPanel2 />
+            );
+        }
+
         return (
             <MatrixClientContext.Provider value={this._matrixClient}>
                 <div
@@ -680,11 +696,7 @@ class LoggedInView extends React.PureComponent<IProps, IState> {
                     <ToastContainer />
                     <DragDropContext onDragEnd={this._onDragEnd}>
                         <div ref={this._resizeContainer} className={bodyClasses}>
-                            <LeftPanel
-                                resizeNotifier={this.props.resizeNotifier}
-                                collapsed={this.props.collapseLhs || false}
-                                disabled={this.props.leftDisabled}
-                            />
+                            { leftPanel }
                             <ResizeHandle />
                             { pageElement }
                         </div>
diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index 7aaedcfb09..69f91047b7 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -347,7 +347,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             Analytics.trackPageChange(durationMs);
         }
         if (this.focusComposer) {
-            dis.dispatch({action: 'focus_composer'});
+            dis.fire(Action.FocusComposer);
             this.focusComposer = false;
         }
     }
@@ -1363,7 +1363,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
                 showNotificationsToast();
             }
 
-            dis.dispatch({action: 'focus_composer'});
+            dis.fire(Action.FocusComposer);
             this.setState({
                 ready: true,
             });
diff --git a/src/components/structures/RoomStatusBar.js b/src/components/structures/RoomStatusBar.js
index dd4b9759d6..65d062cfaa 100644
--- a/src/components/structures/RoomStatusBar.js
+++ b/src/components/structures/RoomStatusBar.js
@@ -26,6 +26,7 @@ import {MatrixClientPeg} from '../../MatrixClientPeg';
 import Resend from '../../Resend';
 import dis from '../../dispatcher/dispatcher';
 import {messageForResourceLimitError, messageForSendError} from '../../utils/ErrorUtils';
+import {Action} from "../../dispatcher/actions";
 
 const STATUS_BAR_HIDDEN = 0;
 const STATUS_BAR_EXPANDED = 1;
@@ -127,12 +128,12 @@ export default createReactClass({
 
     _onResendAllClick: function() {
         Resend.resendUnsentEvents(this.props.room);
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     },
 
     _onCancelAllClick: function() {
         Resend.cancelUnsentEvents(this.props.room);
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     },
 
     _onRoomLocalEchoUpdated: function(event, room, oldEventId, oldStatus) {
diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 49d7e3c238..0ff997ee09 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -55,6 +55,7 @@ import {haveTileForEvent} from "../views/rooms/EventTile";
 import RoomContext from "../../contexts/RoomContext";
 import MatrixClientContext from "../../contexts/MatrixClientContext";
 import { shieldStatusForRoom } from '../../utils/ShieldUtils';
+import {Action} from "../../dispatcher/actions";
 
 const DEBUG = false;
 let debuglog = function() {};
@@ -1162,7 +1163,7 @@ export default createReactClass({
             ev.dataTransfer.files, this.state.room.roomId, this.context,
         );
         this.setState({ draggingFile: false });
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     },
 
     onDragLeaveOrEnd: function(ev) {
@@ -1368,7 +1369,7 @@ export default createReactClass({
                 event: null,
             });
         }
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     },
 
     onLeaveClick: function() {
@@ -1479,7 +1480,7 @@ export default createReactClass({
     // jump down to the bottom of this room, where new events are arriving
     jumpToLiveTimeline: function() {
         this._messagePanel.jumpToLiveTimeline();
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     },
 
     // jump up to wherever our read marker is
diff --git a/src/components/views/elements/ReplyThread.js b/src/components/views/elements/ReplyThread.js
index e7f7196ac6..e96d9ced11 100644
--- a/src/components/views/elements/ReplyThread.js
+++ b/src/components/views/elements/ReplyThread.js
@@ -26,6 +26,7 @@ import {makeUserPermalink, RoomPermalinkCreator} from "../../../utils/permalinks
 import SettingsStore from "../../../settings/SettingsStore";
 import escapeHtml from "escape-html";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import {Action} from "../../../dispatcher/actions";
 
 // This component does no cycle detection, simply because the only way to make such a cycle would be to
 // craft event_id's, using a homeserver that generates predictable event IDs; even then the impact would
@@ -290,7 +291,7 @@ export default class ReplyThread extends React.Component {
             events,
         }, this.loadNextEvent);
 
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     }
 
     render() {
diff --git a/src/components/views/rooms/EditMessageComposer.js b/src/components/views/rooms/EditMessageComposer.js
index b70ef6255c..78c7de887d 100644
--- a/src/components/views/rooms/EditMessageComposer.js
+++ b/src/components/views/rooms/EditMessageComposer.js
@@ -31,6 +31,7 @@ import {EventStatus} from 'matrix-js-sdk';
 import BasicMessageComposer from "./BasicMessageComposer";
 import {Key} from "../../../Keyboard";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import {Action} from "../../../dispatcher/actions";
 
 function _isReply(mxEvent) {
     const relatesTo = mxEvent.getContent()["m.relates_to"];
@@ -157,7 +158,7 @@ export default class EditMessageComposer extends React.Component {
                 dis.dispatch({action: 'edit_event', event: nextEvent});
             } else {
                 dis.dispatch({action: 'edit_event', event: null});
-                dis.dispatch({action: 'focus_composer'});
+                dis.fire(Action.FocusComposer);
             }
             event.preventDefault();
         }
@@ -165,7 +166,7 @@ export default class EditMessageComposer extends React.Component {
 
     _cancelEdit = () => {
         dis.dispatch({action: "edit_event", event: null});
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     }
 
     _isContentModified(newContent) {
@@ -195,7 +196,7 @@ export default class EditMessageComposer extends React.Component {
 
         // close the event editing and focus composer
         dis.dispatch({action: "edit_event", event: null});
-        dis.dispatch({action: 'focus_composer'});
+        dis.fire(Action.FocusComposer);
     };
 
     _cancelPreviousPendingEdit() {
diff --git a/src/components/views/rooms/SendMessageComposer.js b/src/components/views/rooms/SendMessageComposer.js
index 3098c62433..25ad192ea4 100644
--- a/src/components/views/rooms/SendMessageComposer.js
+++ b/src/components/views/rooms/SendMessageComposer.js
@@ -44,6 +44,7 @@ import {Key} from "../../../Keyboard";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import {MatrixClientPeg} from "../../../MatrixClientPeg";
 import RateLimitedFunc from '../../../ratelimitedfunc';
+import {Action} from "../../../dispatcher/actions";
 
 function addReplyToMessageContent(content, repliedToEvent, permalinkCreator) {
     const replyContent = ReplyThread.makeReplyMixIn(repliedToEvent);
@@ -364,7 +365,7 @@ export default class SendMessageComposer extends React.Component {
     onAction = (payload) => {
         switch (payload.action) {
             case 'reply_to_event':
-            case 'focus_composer':
+            case Action.FocusComposer:
                 this._editorRef && this._editorRef.focus();
                 break;
             case 'insert_mention':
diff --git a/src/dispatcher/actions.ts b/src/dispatcher/actions.ts
index 7e76ea5ccb..71493d6e44 100644
--- a/src/dispatcher/actions.ts
+++ b/src/dispatcher/actions.ts
@@ -53,4 +53,9 @@ export enum Action {
      * Provide status information for an ongoing update check. Should be used with a CheckUpdatesPayload.
      */
     CheckUpdates = "check_updates",
+
+    /**
+     * Focuses the user's cursor to the composer. No additional payload information required.
+     */
+    FocusComposer = "focus_composer",
 }