The move by the Electrical Contractors Association and Heating and Ventilating Contractors Association brings the whole industry a step closer to unity.

Both associations have proved staunch defenders of the specialist contractors corner, particulary fighting for fair payment terms with main contractors.

The UKCG represents more than 30 of the country’s largest contractors but has also attracted trade associations to the fold as affliate members.

UK Contractors Group chairman James Wates said: “Specialist engineering contractors will add weight to the group’s activities.

“It has always been my ambition that the industry speaks with a more coherent voice. With UKCG growing from strength to strength and our growing links to the CBI, this is now fast becoming a reality.”

A year ago scaffolding and demolition contractor trade bodies, the NASC and NFDC  joined the group

The move gives the groups an input into the UKCG’s lobbying activity.

The UKCG was set up in 2008 to work alongside the CBI Construction Council, in order to get more direct contact with Whitehall and senior ministers.

ECA chief executive David Pollock said: “We believe it is important that major players in the supply chain are sitting around the same table as main contractors. We share the same goals and challenges.”

Robert Higgs, chief executive of HVCA, said: “We want to play a role in implementing UKCG’s agenda,especially in its business improvement programmes, such as health and safety and the environment.”