Members of Unison and the Association of Professional Ambulance Personnel (APAP) have started working to rule, in a move that will affect over 400 technicians and paramedics at Sussex Ambulance Service Trust.

The action, which started at 0700 GMT on Wednesday, could mean it takes ambulance crews longer to reach emergency calls.

Negotiations over a pay settlement started last summer when the unions asked for a 5% pay increase but were offered 3.6% by the trust.

It means we will inevitably be a little bit slower in our response in some areas where this action is being taken Sussex Ambulance Service Trust spokesman

Since then, despite talks, no agreement has been reached.

Members of Unison and APAP met the ambulance trust and the conciliation service Acas on Wednesday afternoon at the trust headquarters in Lewes to continue discussions.

Unions said the action would continue until an agreement was reached.

Under the work to rule, crews will refuse to work overtime or record details of response times to emergency calls.

Workforce balloted

They will work only from ambulance stations, rather than standing-by near known accident spots.

A spokesman for Sussex Ambulance Service Trust said: "It means we will inevitably be a little bit slower in our response in some areas where this action is being taken."

He said the unions had balloted 704 members in January, of whom 444 - or 45% - had responded. Of these, 349 were in favour.

He said the trust had been limited to an average 3.6% pay increase by an agreement reached nationally between unions and NHS employers.