John Marek has claimed he suffered a smear campaign

Dr Marek - who had been Assembly Member and MP for Wrexham for nearly 20 years - was dropped as the candidate in favour of his former secretary Lesley Griffiths.

It is now being claimed her husband Gareth Griffiths tried to undermine Dr Marek and played an active role in getting him deselected.

A year ago, Mr Griffiths a county councillor wrote to the Wrexham Labour council group chairman saying he was resigning because of John Marek and the party's willingness to support him.

He did not carry out his threat.

But in the letter, Mr Griffiths also made a number of serious allegations against Dr Marek involving his personal integrity.

It was materially no different from any of the things other people said and Lesley would have had to be incredibly prescient to foresee what was going to happen Shan Wilkinson

Dr Marek has described the letter as the "opening salvo in a year-long campaign by certain party members against him".

On Monday night, Lesley Griffiths called the letter "a mistake" but said neither she nor her husband had tried to smear John Marek.

Wrexham Council and Labour group leader Shan Wilkinson told BBC Radio Wales she remembered the letter attacked the process of the trigger ballot.

"There may have been comments about Dr Marek as well but my recollection of it is that, like many of the others that were said and written by members of my group at the time, it expresses great anger about the trigger ballot process which had just taken place.

"I spent a lot of time talking to [Gareth] and other members of my group trying to find a way forward because people were very angry.

"They wanted to do something and what come out of that was a group decision that I should write to the executive and, as everybody seems to know now, that is what actually happened."

Ms Wilkinson rejected the suggestion that the letter compromised Lesley Griffiths' position.

"It was one of many expressions of anger at that time.

Lesley Griffiths won the selection contest

"It was materially no different from any of the things other people said and Lesley would have had to be incredibly prescient to foresee what was going to happen.

"I don't think there is any question of Gareth drumming up anything.

"He was responding and what he said and wrote was the outcome of a very angry discussion which had taken place already."

Ms Wilkinson added she could not understand how the letter had become public.

Dr Marek had previously alleged he was the victim of an unfair smear campaign after losing the reselection battle to Mrs Griffiths by four votes.

He has now appealed to the Welsh Labour Executive to consider whether the vote was a fair one.

Critics had previously accused him of bringing the party into disrepute.

Labour's executive is due to discuss the appeal on Friday, 28 February.