Further disruption is likely at Ealing social services department in west London as the council-wide dispute between management and Unison rumbles on.

A strike called by Unison last week led to three day centres closing for the day. Unison claimed that 1,000 workers from all departments responded to the strike call - the council said the real figure was under 400.

The dispute centres on Ealing's attempt to add an hour to the standard working week for many of its white-collar staff. The council claims it is entitled to do this under the terms of a national agreement but Unison says the agreement is to level standard hours down, not up.

Moves by Unison in March to take the issue to arbitration came to nothing because, according to Unison, the council refused to attend necessary preliminary meetings. Ealing said Unison called a strike without waiting for the outcome of arbitration.

Stephen Barton, one of Unison's negotiation team, said: "We told Ealing, that if they made a reasonable case for exemption [of social services] we were prepared to give it sympathetic consideration. They didn't get back to us.

"Most of my members are low paid members of staff - they can't afford to lose pay by going on strike. But they are very angry." Strikes are planned throughout the summer.