diff --git a/client/src/entrypoints/admin/telepath/blocks.js b/client/src/entrypoints/admin/telepath/blocks.js
index 5d9951b66a..ba987ab479 100644
--- a/client/src/entrypoints/admin/telepath/blocks.js
+++ b/client/src/entrypoints/admin/telepath/blocks.js
@@ -38,30 +38,6 @@ wagtailStreamField.blocks = {
   StreamBlockDefinition,
 };
 
-function initBlockWidget(id) {
-  /*
-  Initialises the top-level element of a BlockWidget
-  (the form widget for a StreamField).
-  Receives the ID of a DOM element with the attributes:
-    data-block: JSON-encoded block definition to be passed to telepath.unpack
-      to obtain a Javascript representation of the block
-      (an instance of one of the Block classes below)
-    data-value: JSON-encoded value for this block
-  */
-
-  const body = document.querySelector('#' + id + '[data-block]');
-
-  // unpack the block definition and value
-  const blockDefData = JSON.parse(body.dataset.block);
-  const blockDef = window.telepath.unpack(blockDefData);
-  const blockValue = JSON.parse(body.dataset.value);
-  const blockError = JSON.parse(body.dataset.error);
-
-  // replace the 'body' element with the populated HTML structure for the block
-  blockDef.render(body, id, blockValue, blockError);
-}
-window.initBlockWidget = initBlockWidget;
-
 window.telepath.register('wagtail.blocks.FieldBlock', FieldBlockDefinition);
 window.telepath.register('wagtail.blocks.StaticBlock', StaticBlockDefinition);
 window.telepath.register('wagtail.blocks.StructBlock', StructBlockDefinition);