Index: tests/data/tab-in-scalar.data
===================================================================
--- tests/data/tab-in-scalar.data	(revision 0)
+++ tests/data/tab-in-scalar.data	(revision 0)
@@ -0,0 +1 @@
+L	S
Index: tests/data/tab-in-scalar.canonical
===================================================================
--- tests/data/tab-in-scalar.canonical	(revision 0)
+++ tests/data/tab-in-scalar.canonical	(revision 0)
@@ -0,0 +1,3 @@
+%YAML 1.1
+---
+"L\tS"
Index: lib/yaml/scanner.py
===================================================================
--- lib/yaml/scanner.py	(revision 385)
+++ lib/yaml/scanner.py	(working copy)
@@ -1322,11 +1322,9 @@
 
     def scan_plain_spaces(self, indent, start_mark):
         # See the specification for details.
-        # The specification is really confusing about tabs in plain scalars.
-        # We just forbid them completely. Do not use tabs in YAML!
         chunks = []
         length = 0
-        while self.peek(length) in u' ':
+        while self.peek(length) in u' \t':
             length += 1
         whitespaces = self.prefix(length)
         self.forward(length)