A conservative Euro-MP last night blamed party rules for provoking a split among activists in their top North-East target seat.
Martin Callanan said new candidate Wendy Morton had been left with a "Herculean challenge" after her selection in Tynemouth left the local party "deeply divided".
Several members are understood to have threatened to resign after Mrs Morton was chosen ahead of high-profile local councillor Michael McIntyre to fight the next General Election.
North Yorkshire-based Mrs Morton, a member of party leader David Cameron's `A-list' of candidates, was chosen by the local 16-strong executive, even though Coun McIntyre is believed to have topped a poll of 600 members. Angry supporters of Coun McIntyre left messages on a Tory grassroots website criticising "muppets down South in party HQ" over the selection, and claiming it had given a boost to sitting Labour MP Alan Campbell, who will defend a 5,532 majority at the poll.
In an attempt to quell the row, Mr Callanan - who is himself on the A-list - left a message on the website speaking of his "increasing dismay" at the split.
But he said the situation had come about because of selection rules which means the full membership does not have the final say.
He wrote: "I know both Wendy Morton and Michael McIntyre very well. At the last election, Wendy did very well fighting a difficult seat in Newcastle and Michael has been one of the key players over the last 10 years in turning the constituency into one of the most effective campaigning organisations in the North of England. It is also true that many of the hardest working activists are strong supporters of Michael.
"The main problem, as I see it, is that the selection was by a small group on the executive rather than at a full general meeting when all members have a vote.
"That makes it much more difficult for people to complain, as it is seen to be more democratic.
"That is not to blame either Wendy or the executive members, who had to operate the system as instructed. Wendy now has a Herculean challenge in persuading some understandably very upset people to campaign for her as the above posts illustrate.
"It saddens me greatly to see a very effective association so deeply divided."
But Conservative frontbencher Alan Duncan, who has been given the remit of Shadow Minister for Tyneside by Mr Cameron, last night signalled his backing for Mrs Morton.
He said: "I'm looking forward to working with Wendy Morton in her election campaign in Tynemouth.
"The Conservative Party is lucky to have a candidate of her calibre.
"Over the past few months, since being appointed shadow Minister for Tyneside, I have seen first-hand the problems which the electorate face: the increasing gap between rich and poor, North and South.
"Wendy and I will be campaigning on issues which are important to all of us, including education, health and transport."
