Hundreds of ambulance workers are on the brink of taking industrial action if they reject a pay deal.

Sussex Ambulance Service Trust staff will be balloted in the next few weeks on whether to accept a three per cent pay rise.

The deal will include incentives such as more pay for working overtime at weekends.

If the offer is thrown out another ballot on industrial action could be held.

Staff rejected a pay deal in September but agreed to unions and managers putting together a plan to improve working conditions including standby and relief cover.

They are also supposed to be working in partnership together to thrash out any concerns over pay and conditions.

Duncan Jones of public service union Unison said: "We have been making progress but there have been good days and bad days.

"There have been some positive steps, such as the overtime at weekends, but there have been some problems with arrangements over study leave.

"There are still some concerns from staff but negotiations are continuing."

Union members claim some senior figures in the trust are not fully committed to the action plan, frustrating the efforts of those managers and staff representatives who are.

A spokeswoman for the service said: "The trust is as committed as ever to working through issues that have been of joint concern to managers, staff and union representatives over recent months.

"We are pleased real progress has been made in addressing some of these issues and will continue to work in partnership with trade union colleagues to progress work on outstanding areas of concern."

Relations between staff and managers have been strained in the last 18 months and reached a low point with industrial action last year.

Workers refused to do voluntary overtime or fill out record sheets giving details of response times.

In October ambulance service chairman Patrick Herbert was sacked after Government inspectors found a culture of bullying and harassment.

Staff said he had been made a scapegoat.

In December the director of operations, Trevor Anderson, resigned after the Audit Commission found irregularities in figures for ambulance response times.

Sussex is one of the busiest ambulance services in England, covering a population of 1.5 million and dealing with an average of 600 emergency calls a day.