LONDON (AP) _ Negotiators reached agreement today on a pay raise of about 17 percent for ambulance workers to end a dispute that has disrupted emergency service across Britain for six months.

Some ambulance drivers said they would vote against the deal because it did not put them on the same footing as police and firefighters by including a formula for future wage increases tied to inflation.

But Roger Poole, chief negotiator for the five unions involved, called the pay deal ''simply staggering'' and said the ambulance unions had ''driven a coach and horses'' through the government's policy on curbing wage hikes.

The accord, covering the period from March 1, 1990 until March 31, 1991, was reached after 20 hours of talks between union officials and managers of the National Health Service.

Poole said it gives ambulance workers a 17.6 percent pay increase, while the Health Service put the package at 17 percent. There is an option for local ambulance companies to add another 2 percent.

The salaries of ambulance workers would rise from $17,259 to $18,812 on March 1 and to $20,298 on Oct. 1. Crew members would also receive a lump sum payment of $1,454, and there would be extra allowances for staff with specialized training.

Poole said he was confident the 22,500 ambulance workers and control room staff would overwhelmingly approve the settlement and return to their jobs after a vote is taken around March 13.

In the Liverpool area, branch secretary Ray Clayton of the National Union of Public Employees said he was dismayed there was no pay formula to link wage increases with inflation. ''I don't think the strike will be called off,'' he said.

Andy Lawrence, an ambulance workers' spokesman in west Sussex, called the deal ''an insult to our intelligence.''

Job actions began Sept. 7 when ambulance drivers started refusing to work overtime. In October, emergency crews stopped using their radios or in some cases answering calls from control rooms.

Prime Minister Margaret Thatcher's government ordered police and army ambulances to answer emergency calls starting Nov. 8. It was the first time they had been used for civilian ambulance calls since the ''winter of discontent'' of 1978-79 when a series of public service strikes hit a Labor Party government.

Some health authorities hired taxis and asked relatives to drive non- emergency cases to hospitals.

In some cases, ambulance crews suspended for joining the dispute carried out their own unofficial service, accepting emergency calls direct from hospitals or members of the public but not from ambulance control rooms.