Travel around the M25 will be severely disrupted by strikes among Balfour Beatty maintenance workers after they voted to down tools in a row over pay, the Unite union has warned.

Around 150 staff who maintain the entire London orbital motorway said they were angry at the “meagre pay offer” proposed by employer Balfour Beatty of 3.4%.

The workers operate out of depots based in Barnet, Uxbridge, Swanley, Epping and Dartford and Unite said strike action would cause serious disruption to journey times.

The union said that with the retail price index currently at 4.9%, the pay offer was a real terms pay cut and that this came on top of a below inflation pay rise last year.

It added that dates for industrial action would be announced in the coming days.

Unite regional officer Phil Silkstone said: “The inconvenience and delays caused by strike action to M25 travellers sits squarely at the door of Balfour Beatty.

“It has had every opportunity to put forward a reasonable offer but has repeatedly refused to do so. Balfour Beatty must swiftly return to talks with Unite and table an acceptable pay deal.”

A Balfour Beatty spokesperson said: “We are disappointed by Unite the Union’s decision to proceed with strike action. 

“We remain committed to working with them to reach an appropriate outcome, and would like to reassure travellers that suitable contingency plans are in place to minimise any potential disruption.”