UNITE has called on the Labour leadership to bring an immediate halt to the troubled selection process for choosing a General Election candidate in Falkirk.

The union wants the matter to be discussed urgently by all members of the party's ruling National Executive Committee.

It comes as Conservative HQ is urging the Information Commissioner to look into what it says is a potential breach of the Data Protection Act.

One of the allegations made in the continuing row over selecting a new candidate in the Falkirk Constituency Labour Party (CLP) is one person found he and two relatives had been enrolled as members without filling in or signing any forms. Under law, consent has to be given for processing personal data.

Tory Party chairman Grant Shapps said: "Day by day an unaccountable and unelected union baron is strengthening his vice-like grip on the Labour Party.

"If Ed Miliband won't stand up to the likes of Len McCluskey in his party, there's no way he could stand up for the interests of this country."

Last week, following a meeting of NEC officers, Falkirk was put on "special measures" effectively taking the selection process of finding a new candidate following the resignation of disgraced MP Eric Joyce out of the the local party's hands and putting it under central control.

The NEC officers found "sufficient evidence of concern" about membership lists after claims were made Unite had stuffed Falkirk CLP with members to ensure its preferred candidate was chosen; claims denied by the union. A "freeze date" of March 2012 was introduced, effectively disbarring almost half of the local membership.

Last month, Lord Mandelson, the former Business Secretary, aired concerns that trade unions were seizing control of many candidate selections.

Kim Howells, the former Labour Foreign Office Minister, said the row threatened "the whole reputation of the Labour Party" and it was it was "absolutely crazy" to let unions pay the party membership fees of their members.

David Blunkett, the former Home Secretary, yesterday urged the Labour leadership to publish the internal report, saying the party "should be as transparent as possible".

Len McCluskey, Unite's General Secretary, has threatened legal action over the Falkirk row, having claimed angrily the Labour leadership had succumbed to "Blairite pressure" and that his members had been the victim of a smear campaign.

Last night, the union issued a new statement, saying the decision to "rush ahead" with the selection process, denying a vote to 150 or so members and imposing a short list was "without any justification and is a further breach of democratic procedures and natural justice". It said it had written to Iain McNicol, Labour's General Secretary, "demanding this process was halted immediately, pending a full discussion at the party's NEC".

Unite said it had been able to see a copy of the internal report, which had confirmed to it that the taking over of the process by the party centrally and the disenfranchisement of more than 100 local members was "at best an extreme over-reaction, at worst the product of an anti-union agenda".

It pointed out how the internal investigation "apparently drew on material supplied by another candidate for the Labour selection", which would inevitably cast doubt on its objectivity, given Unite was allowed no opportunity to see or hear the allegations before the party had decided to act on them.