A West Midlands UKIP MEP has been told he cannot stand for the party in the next European elections.
Mike Nattrass, who has been both chairman and deputy leader, was told he failed a candidate assessment.
He said: "I just want the members to decide who should stand, that's what the party rules say but those rules have been broken."
In May 2012 he said he would retire before the European elections in 2014, but changed his mind shortly after.
UKIP's candidate selection process involves a two-hour assessment which includes public speaking, an interview and a written test.
Applicants are graded and those with the top grade are placed on the party's national approved list of candidates.
Mr Nattrass has employed a lawyer to challenge his grading and said he still "totally supports the principles of UKIP".
He said a number of "high profile" other candidates had been excluded.
His constituency covers Herefordshire, Shropshire, Staffordshire, Warwickshire, the West Midlands and Worcestershire.