Skilled staff, including fitters, electricians and plumbers, at the hospital will join colleagues at Doncaster Royal Infirmary and Bassetlaw Hospital in staging a walkout tomorrow - and again on March 17, 20 and 25.

The move follows the failure of recent talks between leaders of union Unite and bosses at Doncaster and Bassetlaw Hospitals NHS Foundation Trust that involved conciliatory service ACAS.

About 25 craftsmen are involved in the action and make up about a third of maintenance staff employed across the trust's sites.

Unite claims the hospital trust is one of the last 'maverick' employers failing in their obligation to pay a national recruitment and retention premium (RRP) agreed under Agenda For Change - a major restructure of pay and conditions which took effect on October 2004.

Certain posts were identified as needing such an incentive as new grades fell below similar pay rates outside the health service. Workers staged four days of strike action during November last year.

Unite's head of health Kevin Coyne claims that two tribunals in Newcastle and Lancashire have now ruled that there is a contractual right to RRP but this was "still resisted, unreasonably" by the trust.

He said: "The position of the trust was that they would not pay RRP to new starters post October 1, 2004, or to supervisors and that they would not be prepared to pay the others until a productivity agreement had been signed which made the deal self-financing and included items that were frankly outlandish."

Unison craft members at the trust are being balloted on similar action.

A spokeswoman for the trust said: "We are disappointed at the decision of UNITE to ask its members to take further industrial action later in March. Only a small number of staff are taking part in this action and the trust is already making plans to ensure that patient care is not adversely affected."