M&E employers and union representatives from the Heathrow Terminal 5 site were locked in talks to prevent industrial action over travel pay, as Building went to press.

M&E union Amicus wants pay parity with building workers on the project who receive the money. Amicus argues that although the builders’ deal was a local agreement, it has since become a national pay arrangement.

Amicus also feels that travel pay ought to be paid because the scheme is so large that moving around the site adds considerable time to the working day.

Representatives of leading firms on the site, including contractors Crown House Engineering and Amec, have offered improved travel arrangements and the use of a 1000-space car park for the workers. However, this would not come into effect until next year.

The employers claim that to give the extra allowance would cost an additional £37m and that this is not feasible.

The meeting, which was being held in a central London hotel on Wednesday, is understood to be the last round of the official disputes procedure.

Amicus is collecting the details of hundreds of M&E workers in preparation for a ballot on strike action or industrial action short of a strike.

A source close to the negotiations said that the stance of the employers was that the unions ought to have addressed this issue when they originally signed the industrial relations agreement for the T5 site.