Charles Clarke has blasted the Labour disciplinary procedures that led Ian Gibson to resign from his Norwich constituency and have triggered a potentially very damaging by-election for the party in the city.

Charles Clarke has blasted the Labour disciplinary procedures that led Ian Gibson to resign from his Norwich constituency and have triggered a potentially very damaging by-election for the party in the city.

He and many other Labour MPs felt that Dr Gibson had been 'badly treated', he said, by the decision of the party's national executive committee star chamber to drop him as a parliamentary candidate.

The former Norwich North MP had presented himself with a case to answer, he conceded, through allowing his daughter to live rent-free at his London flat on which he was claiming the MPs' second-home allowance - and then by selling it to her at a price well below the market value.

Dr Gibson had not explained these matters as well as he could have done, he said, and there was still some 'confusion'. But he added: 'I think it's a shame that he has decided to resign and that there's a by-election. It didn't have to work out like this. He could have carried on.'

The Norwich South MP and former home secretary complained that Dr Gibson had been dealt with by procedures featuring 'a total lack of transparency', and had been 'summoned arbitrarily'.

'The party needs a proper set of procedures, with a clear set of rules and criteria that distinguish between people who have broken the law and others who have made bad judgments over their houses and other claims,' he said. Instead, it had arrangements 'based on vigilantism and the Daily Telegraph' and 'driven by the desire of the prime minister for scapegoats'.

Dr Gibson had a majority of 5,459 over the Tories in the 2005 general election, and that looks very vulnerable in the light of his party's trouncing in the European Parliament and county council elections.

But Labour had every chance of successfully defending the seat in the by-election, Mr Clarke emphasised, 'if we make our case'.

He also warned that the Greens would be 'a real threat' in the by-election after showing their electoral strength in the city last week by coming first in the European election and winning seven county council seats there.

But he launched into criticism of Norwich Green city councillor Rupert Read who headed his party's slate of Strasbourg candidates in the eastern region, and advised the Greens not to choose him as their Norwich North candidate.

Mr Clarke would not be drawn on the issue of whether Labour should opt for a quick by-election next month, or whether it should wait until the autumn.