More than 150 Unison union members marched through Oxford in the opening salvo of their campaign for a regional weighting allowance.

The union called the demonstration, which processed through Bonn Square, Queen Street, Cornmarket and Broad Street yesterday lunchtime, to press for the introduction of an Oxfordshire allowance for all public sector workers to offset the high cost of living in the county.

At present, Thames Valley Police officers, but not support staff, who joined the force after September 1, 1994, receive a £2,000 a year cost of living allowance.

Some NHS staff in Oxfordshire also receive supplements of between £400 and £600 - although the bulk of staff do not. Unison's Oxford City branch secretary, Martin Gregory, said: "This is really our opening shot, and our first public event.

"The Government must do something urgently to help all of Oxfordshire's public services get properly staffed up.

"What they have done for the police should be applied across the board.

"It is grossly unfair and insulting to underpaid and hardworking staff that the Government has only acted for certain health professionals and the police." He added: "The public services depend on us all. We reject the Government's concept of keyworkers. We are all key and vital to seeing to the needs of the public.

"The march was good, although the turnout was a bit lower than we had hoped for. I think it got the message across, because it was a very visual - people were carrying banners and placards with slogans like 'low pay, no way' and 'Oxon allowance for the Oxon prices'." He added: "This is the first part of what we recognise is going to be a longish campaign to get pay supplements throughout the services."

Mr Gregory said a weighting allowance could ease recruitment problems in the public sector, which are being compounded by rising house prices.

Last year, house prises in the county rose by 25 per cent, according to the Land Registry - higher than the average rise in London or the south east.