2nd class Large blue Machin security stamp from retail booklet 2011
The retail booklets of 4 stamps were reissued on 22 March 2011 without the printer's name on the back cover.
This is the 2nd class Large Letter NVI stamp printed by Walsall Security Print in booklets.
The year code MA11 is now just above the letters 'ge'; the source code on these booklets of 4 is still MFIL and has been moved to the lower right 'paperclip'.
Coded MA11 MFIL - SG U2970 (also used for later years)