diff --git a/src/calibre/ebooks/chardet/__init__.py b/src/calibre/ebooks/chardet/__init__.py
index 8c101f9de5..dd279c6559 100644
--- a/src/calibre/ebooks/chardet/__init__.py
+++ b/src/calibre/ebooks/chardet/__init__.py
@@ -32,7 +32,7 @@ def detect(aBuf):
ENCODING_PATS = [
re.compile(r'<\?[^<>]+encoding\s*=\s*[\'"](.*?)[\'"][^<>]*>',
re.IGNORECASE),
- re.compile(r''']+?content\s*=\s*['"][^'"]*?charset=([-a-z0-9]+)[^'"]*?['"][^<>]*>''',
+ re.compile(r''']*?content\s*=\s*['"][^'"]*?charset=([-a-z0-9]+)[^'"]*?['"][^<>]*>''',
re.IGNORECASE)
]
ENTITY_PATTERN = re.compile(r'&(\S+?);')