Union sources claim Glasgow is to be used as a pilot area for controversial benefit reforms to be announced today, but details of the city's involvement in the scheme are being held back until after this week's by-election.

Conservatives at Westminster leaked details of the plans three days ago, claiming the credit for ideas such as forcing the long-term unemployed to work for their dole and looking to slash the numbers on incapacity benefit.

Sources at the Public and Commercial Services union told The Herald that they had been told by the Department of Work and Pensions that pilot areas for trying out the new policies had been identified, but an announcement of this had been shelved because of the by-election.

"We understand the changes will be pushed through as part of the City Strategy scheme of which Glasgow is already a part, but that this cannot be announced this week," said one official.

"Other parts of the scheme, such as paying private companies a bounty for ever person they get off benefit, have already been rubbished by the Commons Public Accounts Committee.

"That strategy was found to result in corruption when it was tried in the United States."

Glasgow East constituency comes in the UK top 10 for measurements of those seeking work, on support for low income or on Incapacity Benefit/Severe Disablement Allowance. On that latter measure it is at number one in the UK with 9920 claimants.

Tories hailed the leaked Green Paper as a direct copy of their own policies, with its stress on "no right to a life on benefits" and plans to pilot projects to test "compulsory full-time activity" for the long-term unemployed.

The Solidarity candidate in Thursday's by-election, Tricia McLeish, said: "Labour are planning to cut the income of the poor people of Glasgow in order to steal the Tories' clothes and woo middle-class English voters.

"They are also going to privatise social security by paying private companies £50,000 for every claimant they get off benefit, yet where this has been tried abroad it has led to destitution for the poor and widespread corruption."

Publicity surrounding The Green Paper, due to be formally published today, will add spice to the final days of campaigning in the by-election.

Frances Curran, the Scottish Socialist candidate, said yesterday: "This is a new low even for today's Labour Party - to find their attacks on the sick and unemployed warmly welcomed by the heirs of Thatcher." Labour reacted angrily yesterday to a report by a young Sunday newspaper journalist who posed as a volunteer and told the inside tale of a gaffe-ridden campaign, lacking activists and with a main computer system that had broken down.

Scotland Office minister David Cairns responded: "If people want to come in, mislead people about their intentions, be taken into people's confidence and then betray that confidence for money, that is their lookout, but we have an election to run."

Mr Cairns said of the campaign: "We will be pounding the streets relentlessly from now until five to 10 on Thursday night. We are in very good spirits.

"We set a target on Friday night to knock on 20,000 doors, and we are well over half way. The reception is genuinely really good. You get a bit of apathy, as you always do, but we don't think our vote is collapsing, far from it."

The SNP say they welcomed so many activists to the city over the weekend that they were able to get a leaflet drop round every home in the constituency and then do a second delivery round many homes featuring a message of support from Clydeside legend Jimmy Reid.

The former shipyard leader said in it: "I know many people in the East End have voted Labour all their lives and that after years of loyalty to Labour, deciding to vote for another party is not easy.

"I understand that because it's a journey I've made myself. It wasn't so much I left Labour. I felt they left me. Any doubt I had about that was cast aside forever when I watched Gordon Brown cosying up to Margaret Thatcher in Downing Street last year."