An FA hearing upheld the decision on Tuesday afternoon, meaning the Belgium defender will now serve a one-match ban.
The sanction rules Vermaelen out of the Barclays Premier League match at Birmingham on Saturday, when manager Arsene Wenger will also be without injured centre halves William Gallas and Johan Djourou.
This doesn't look good: Branco goes down after Vermaelen's challenge.
. the Arsenal man is sent off .
. but manager Arsene Wenger is on hand to inform him they will be appealing against it
The FA said in a statement: 'At a Regulatory Commission hearingtoday, a claim for wrongful dismissal from Arsenal defender ThomasVermaelen was dismissed.
'Vermaelen was shown a red card for denying an obvious goalscoringopportunity during Arsenal's match against West Ham United on Saturday20 March.
'He will now serve a one match suspension with immediate effect.'
Defender Vermaelen was ordered off shortly before half-time at theweekend for bringing down Guillermo Franco inside the penalty area andfaces a one-match ban.
Arsenal were leading 1-0 and went on to win 2-0, with West Ham'sAlessandro Diamanti missing the penalty which followed Vermaelen'sdismissal.
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