Motorists on the M25 could face delays as 150 motorway maintenance workers decide whether or not to strike over pay conditions.

Employees at Balfour Beatty usually work across the orbital network and are set to ballot about a decision in the near future.

The workers are angry at the international construction firm, which has offices in Medway, over an offer of 3.4%, with the Unite union claiming this is essentially a “pay cut” due to inflation.

Unite general secretary Sharon Graham said: “Balfour Beatty is an immensely profitable company that can afford to put forward an offer that reflects rising living costs.

“Its M25 workers have Unite’s total backing in demanding a fair pay rise.”

Balloting from the workers will begin this week and close on March 12, with strikes expected soon after if a resolution is not found.

Unite regional officer Phil Silkstone added: “Balfour Beatty can stop this dispute from escalating and causing disruption to the smooth running of the M25 by tabling an acceptable offer.

“It has more than enough profits to do that.”

The M25 is a 117-mile stretch of motorway and is one of the most important roads in the UK, as well as one of the busiest.

Ex-Prime Minister Margaret Thatcher opened the final section in 1986, making the M25 the longest ring road in Europe when it opened.

The Dartford Crossing completes the orbital route but is not classed as a motorway and is instead referred to as a trunk road and designated as the A282.

A Balfour Beatty spokesperson said: “We continue to work closely with Unite the Union to reach an appropriate outcome.”