Early indications show that more than 70% of M&E workers have signed the new agreement which triggered angry protests from union Unite activists around the country.

While the overall figure stands at around seven out of 10 of the workforce, contractors are reporting some areas of their business are even higher.

Balfour Beatty Engineering Services has seen 95.5% of contracts returned from employees in their building services division.

Some of the companies’ regional offices are still gathering signed contracts, so the overall response rate may change.

Blane Judd, the HVCA’s chief executive, said: “We’re extremely encouraged by this early feedback.

“I’ve spoken with the companies and all of them are confident that more positive responses will follow as people review the facts about BESNA and what it means for them.”

“This agreement is vital for the future of our industry; it will help to secure jobs and win new contracts.”

Peter Lewis, chief executive, Shepherd Engineering Services, said: “The response from our employees has been very positive.

“To be frank, our complete focus on this issue has been on ensuring an exhaustive, detailed and transparent engagement with our people. We have spent an awful lot of face to face time on this.

“Ninety-two per cent of our work force have signed up for the BESNA arrangements and that total is increasing daily. When it has come to rational discussion and dealing with any original concerns that have come from the wider publicity, our employees have engaged with us in a really proactive way.

“They have agreed, understood and supported the need to modernise how we do things and the benefits BESNA will bring everyone. We have always seen this as a way of making sure we can maximise direct employment well into the future.”

Martin Bailey from NG Bailey, added: “Over 90% of our workforce have signed and returned their contracts to date, a figure which continues to rise.

“It is clear from discussions with our employees that they understand the importance of the BESNA and are not persuaded by the sensational headlines, such as the notion that workers will get a pay cut.”

Seven major building services contractors are introducing the new agreement with the Heating and Ventilating Contractors’ Association from April.

The new BESNA will bring pay parity across all trade disciplines, resulting in increases for nearly a third of workers.

Contractors have argued it will safeguard jobs, allowing them to compete for work, and offer upskilling opportunities for many employees.

The seven companies working with HVCA to introduce BESNA are: Balfour Beatty Engineering Services, Crown House Technologies, Gratte Brothers, NG Bailey, Shepherd Engineering Services, SPIE Matthew Hall and T Clarke.

Any workers who do not sign and return their contracts this month will be contacted by their employer to discuss any concerns that they may have.

A series of one-to-one meetings have already taken place at some companies and many employees signed their new contracts once their remaining questions were addressed.