Party workers in Sheffield believe their soft-left MP, Mr Blunkett, is being targeted by extremists from the hardline Socialist Organiser group. After offering to mediate between the leadership and Dave Nellist, former MP for Coventry South East, Mr Blunkett eventually agreed to his expulsion when he refused to disown the Militant Tendency.
About 15 known Yorkshire extremists are believed to have transferred into Mr Blunkett's Sheffield Brightside constituency. One party member connected with Socialist Organiser was recently refused membership when he attempted to move into the constituency.
Any resurgence of far-left activity would be a setback for John Smith, the Labour leader, following the acrimonious expulsion of Militant Tendency supporters in the Kinnock years.
Mr Blunkett said last week: 'I am saddened that particular groups in the Labour Party should use these disgraceful, undemocratic and unconstitutional methods. They do not seem to accept that they have lost the battle of ideas so they resort to these tactics.'
In the national ballot, Mr Blunkett came second to Neil Kinnock with 531,000 votes, representing the backing of 531 constituencies.
The fraud came to light when the fake ballot papers produced a better than expected result for the left-wing Campaign Group slate. In Bassetlaw the number of forgeries was about 40. In Sheffield Brightside the number was significantly lower although they were said to represent 18 per cent of the vote.
Apart from the quality of paper, the forgeries were easily detected by the party's director of organisation, Joyce Gould, because the original ballot papers were perforated.