Kirtley's action also came under scrutiny in 2001

The England and Wales Cricket Board ordered him to undergo the assessment at its National Cricket Centre after he was twice reported last season.

An expert from Loughborough University, Dr Mark King, concluded that Kirtley's action exceeded the maximum 15 degrees "elbow extension" allowed by the ICC.

He cannot bowl until a further analysis shows he has corrected his action.

A year ago, the International Cricket Council relaxed the laws, which had previously permitted only five degrees of tolerance for spinners and 10 for fast bowlers.

Kirtley, 30, has been told he can call on the help of England bowling coach Troy Cooley to help him make the adjustments he needs.

Sussex manager Mark Robinson said: "We are obviously disappointed for both James and Sussex.

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"The club is looking to digest and analyse the information in order to formulate the right plan for the way ahead."

Kirtley played a key role in Sussex's County Championship success of 2003.

He appeared in four Tests for England that year and was part of the one-day squad as recently as April, 2004.

His international debut, in Zimbabwe in October 2001, was marred when his action was reported by the match referee and he subsequently underwent remedial action to modify it.

He has hyperextensive elbows, which means they bend backwards slightly, and this has in the past been blamed on an appearance of throwing.