diff --git a/src/fixes/node-fixes/class-space-collapse-fix.php b/src/fixes/node-fixes/class-space-collapse-fix.php
index 11a3b22..158a3fc 100644
--- a/src/fixes/node-fixes/class-space-collapse-fix.php
+++ b/src/fixes/node-fixes/class-space-collapse-fix.php
@@ -41,8 +41,11 @@
  */
 class Space_Collapse_Fix extends Abstract_Node_Fix {
 
+	// Use the PCRE-escaped non-breaking space so the /x modifier doesn’t strip it out.
+	const PCRE_ESCAPED_NO_BREAK_SPACE = "\\x{00A0}";
+
 	const COLLAPSE_NORMAL_SPACES            = '/[' . RE::NORMAL_SPACES . ']+/Sxu';
-	const COLLAPSE_NON_BREAKABLE_SPACES     = '/(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')*' . U::NO_BREAK_SPACE . '(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')*/Sxu';
+	const COLLAPSE_NON_BREAKABLE_SPACES     = '/(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')*' . self::PCRE_ESCAPED_NO_BREAK_SPACE . '(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')*/Sxu';
 	const COLLAPSE_OTHER_SPACES             = '/(?:[' . RE::NORMAL_SPACES . '])*(' . RE::HTML_SPACES . ')(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')*/Sxu';
 	const COLLAPSE_SPACES_AT_START_OF_BLOCK = '/\A(?:[' . RE::NORMAL_SPACES . ']|' . RE::HTML_SPACES . ')+/Sxu';