diff --git a/src/calibre/ebooks/oeb/polish/utils.py b/src/calibre/ebooks/oeb/polish/utils.py
index 12671dbd2f..23b573857f 100644
--- a/src/calibre/ebooks/oeb/polish/utils.py
+++ b/src/calibre/ebooks/oeb/polish/utils.py
@@ -205,3 +205,14 @@ def apply_func_to_html_text(match, func=icu_upper, handle_entities=handle_entiti
     parts = (x if x.startswith('<') else f(x) for x in parts)
     return ''.join(parts)
 
+def extract(elem):
+    ''' Remove an element from the tree, keeping elem.tail '''
+    p = elem.getparent()
+    if p is not None:
+        idx = p.index(elem)
+        p.remove(elem)
+        if elem.tail:
+            if idx > 0:
+                p[idx-1].tail = (p[idx-1].tail or '') + elem.tail
+            else:
+                p.text = (p.text or '') + elem.tail
diff --git a/src/calibre/srv/render_book.py b/src/calibre/srv/render_book.py
index 73cc923ea0..272212ebbd 100644
--- a/src/calibre/srv/render_book.py
+++ b/src/calibre/srv/render_book.py
@@ -24,6 +24,7 @@ from calibre.ebooks.oeb.iterator.book import extract_book
 from calibre.ebooks.oeb.polish.container import Container as ContainerBase
 from calibre.ebooks.oeb.polish.cover import set_epub_cover, find_cover_image
 from calibre.ebooks.oeb.polish.css import transform_css
+from calibre.ebooks.oeb.polish.utils import extract
 from calibre.ebooks.css_transform_rules import StyleDeclaration
 from calibre.ebooks.oeb.polish.toc import get_toc
 from calibre.ebooks.oeb.polish.utils import guess_type
@@ -96,17 +97,6 @@ def check_for_maths(root):
             return True
     return False
 
-def extract(elem):
-    p = elem.getparent()
-    if p is not None:
-        idx = p.index(elem)
-        p.remove(elem)
-        if elem.tail:
-            if idx > 0:
-                p[idx-1].tail = (p[idx-1].tail or '') + elem.tail
-            else:
-                p.text = (p.text or '') + elem.tail
-
 def has_ancestor(elem, q):
     while elem is not None:
         elem = elem.getparent()