Conservative in-fighting over the conduct of Norfolk County Council leader Derrick Murphy has escalated after one constituency association urged a neighbour to consider allegations he had brought the party into disrepute.

The letter sent by South West Norfolk Conservatives' chairman Lady Kay Fisher to party leaders in South Norfolk highlights national party rules that allow associations to expel members.

Such a move could threaten Mr Murphy's County Hall career because anyone whose expulsion from a local Tory association is confirmed by the national party is removed from the national membership list and cannot contest elections for the party.

Mr Murphy dismissed the allegations against him as 'tittle-tattle' and 'nonsense' and said he was the victim of a dirty tricks campaign because of his support for the King's Lynn incinerator, which put him at loggerheads with Conservative-run West Norfolk Council.

He said the letter contained 'a considerable number of factual inaccuracies' and he had sent a 'robust rebuttal' to the national, regional and local Conservative party chairmen.

Mr Murphy currently represents the Freebridge Lynn division, the site of the proposed incinerator at Saddlebow, but in May it was announced he would fight the Forehoe division, 50 miles away, for South Norfolk Conservatives in next year's county council elections.

The EDP understands Lady Fisher's letter alleges his conduct damaged the Conservative campaign in the recent Mid Forest by-election for Breckland Council - a claim Mr Murphy said was 'arrant nonsense'.

South West Norfolk Conservatives' executive council voted to send the letter by a 'substantial majority' at a meeting on August 3.

David Pope, an executive council member and West Norfolk Council cabinet member, said: 'We are trying to keep pressure on him all the time and make some of the county councillors think 'We are getting in a bit of a hole and elections are coming up and is he our talisman' and we will see what happens.

'We are against the incinerator and he is obviously in favour of it and we are trying to use every means available to us to try to stop it and he is using all the means he has to get it done.'

South Norfolk Conservatives are already due to consider calls from two individuals to expel or deselect Mr Murphy at a management team meeting on August 28. He has said the complainants had 'absolutely no evidence on which to base their statement'.

News of the letter comes after it was revealed that North West Norfolk Conservative Association has written to the Conservative Party's co-chairman, Baroness Warsi, about Mr Murphy's conduct, saying that despite his 'undoubted skills' he has the 'propensity to sow divisiveness' and 'pursue personal vendettas against those who oppose him' in a way which is damaging the party electorally.

Involvement of the Tory party at national level increases the pressure on all sides.

*Meanwhile it has also emerged that the political assistant at the centre of a email row which deepened divisions among Norfolk Tories has resigned.

The email was sent in April to BBC Radio Norfolk by Kevin Vaughan, political assistant to the Conservative group at County Hall, two days before Nick Daubney, leader of West Norfolk Council. was due to appear on Nick Conrad's show to discuss the incinerator.

It suggested it might 'be pertinent information' for the broadcaster to know that the borough council leader was facing 'a serious leadership challenge' and that his authority had failed to procure alternative technology to the plant.

When the email came to light it sparked an independent investigation at County Hall, which last month concluded that Mr Vaughan had acted on the wishes of Mr Murphy.

Mr Vaughan, who was employed by he county council, not the Conservative group, has now resigned.

Anne Gibson, head of human resources and organisational development at County Hall, said: 'Kevin's role as political assistant was due to come to an end on August 8 and he declined an offer to be considered for redeployment elsewhere within the authority.

'The county council has paid Kevin the sum due to him contractually, plus an additional sum in recognition of the difficulties of the last few months.'

She also revealed the council's own monitoring officer had investigated reports that the independent investigator's report had been circulated to members of the public.

She said: 'In addition, it has been reported that copies of the investigator's report had been passed to members of the public unconnected with the investigation. The monitoring officer has thoroughly investigated this allegation and found no evidence that it was true.'