MPs are set to ambush Tony Blair in an effort to win justice for workers "robbed" of their pension when their companies went bust.

Five North-East Labour MPs have signed a parliamentary motion demanding that the Government compensates staff who have lost their nest egg for retirement.

The MPs are expected to try to amend the Pensions Bill which will compensate workers affected after 2005, but not those who have already lost out.

Campaigners believe up to 20,000 people have been affected after the scheme they had paid into for years was wound up.

Concern has been raised over pensions at royal carpet manufacturer Carpets International, which axed 74 jobs at its Hartlepool factory after going into receivership last summer.

There is also concern for workers at construction company Ballast plc, which was placed in administration in October. It employs 1,000 staff and has a plant at Billingham, Teesside.

More than 140 Labour backbenchers are demanding retrospective compensation - threatening the Government with defeat when the Pensions Bill reaches the Commons.

They include Vera Baird (Redcar), Frank Cook (Stockton North), Kevan Jones (Durham North), John Cummings (Easington), Gerry Steinberg (City of Durham) and Bill Etherington (Sunderland North).

Under laws introduced after the Maxwell pension scandal, any money left in a company scheme goes first to retired workers. It means staff who are nearing retirement can find themselves left without a penny, forcing them to remain in work longer.

Ministers have insisted the legislation cannot compensate those who have already lost out, fearing the bill will run to hundreds of millions of pounds.