The ban was imposed in 1994 by Michael Howard, the then Conservative home secretary. It is to be scrapped in return for an overhaul of working practices and a three-year pay deal.
The strike ban led to annual protests by the TUC which saw it in the same light as the Thatcher government's prohibition on trade union membership at GCHQ, the government's electronic eavesdropping centre.
Mr Blunkett will urge the Prison Officers' Association (POA) to accept his offer when he addresses the union's annual conference in Southport today. He is the first senior Labour figure to make a speech at the conference since 1994, when John Prescott promised to restore its trade union rights and take private prisons back into public ownership.
The Home Office minister Beverley Hughes was booed when she addressed last year's conference. The union was accused of orchestrating the heckling after it sent out a press release announcing that she would be booed. It is not certain that an offer to restore full trade union rights will be enough for Mr Blunkett to secure a modernisation deal.
The offer is believed to involve a three-year pay deal with a voluntary no-strike clause to replace the current annual pay round. It would be linked to better training and more flexible working practices.
The POA's national chairman, Colin Moses, one of the UK's few black trade union leaders, has restrained members from taking unofficial action over the last year and defused opposition to privately managed prisons. Mr Moses welcomed the offer yesterday saying he believed the ban was imposed more out of spite than common sense.
