The FA are to ban all Wembley corporate seat supporters of Manchester United and Crystal Palace from wearing their club colours at the FA Cup final on Saturday.
All 15,000 season ticket holders with access to Club Wembley and Bobby Moore Club hospitality areas of the stadium have received emails this week telling them that they risk being ejected - even for wearing a club lapel badge on a jacket.
Replica shirts had never been allowed in the Club Wembley seats but the club branding clothing restrictions that 'will be strictly enforced' now extend to scarves, hats, flags, foam hands and any clothing items, including club ties, bags, face paint, badges and lanyards.
The 'No Club Colours' crackdown introduced by FA management follows a number of ugly confrontations that took place between rival fans in the corporate hospitality areas across the semi-final weekend when Watford were beaten by Crystal Palace and Manchester United defeated Everton.
The email from the Club Wembley Team reads: 'This rule has never been extended to other items than replica shirts; however, due to a number of incidents at recent events, a "No Club Colours" policy is being introduced and will be strictly enforced from the Emirates FA Cup final.
'Should club colours be worn, you may be refused entry or be removed from the stadium for your own safety.'