Contractor bodies have become so concerned about the situation that they are lobbying MPs for a reform of the Self-Employment Income Support Scheme (SEISS).

Latest government figures show 659,000 self-employed construction workers claimed £2.3bn in grants during last December alone when the latest round of the scheme opened.

The Association of Brickwork Contractors has been contacted by a number of leading firms worried about the situation.

Association Chief Executive Officer Eve Livett said the grant scheme was crucial during the first lockdown but has been open to abuse since as the industry continued working during subsequent shutdowns.

She said: “These grant payments appear to have been designed to be very accessible with criteria and benchmarks for approval set very low.

“Whilst this was key to ensuring financial stability for workers in the initial lockdown period, this is now demonstrably counterproductive for our industry and it is felt that a shift in strategy is required in order to mitigate the issues arising from it.

“As the trade body for brickwork contractors, we have had reports of workers successfully applying for grants despite demand for work being unaffected, with the workers themselves continuing to work throughout.”

One leading brickwork contractor added: “These payments have caused a situation where workers don’t need to work.

“Some foreign workers have taken the money and disappeared back home with no plans to return and it is causing catastrophic labour shortages.”

The drylining sector is also being hit hard by skills shortages.

One specialist said: “We usually have a large pool of labour-only subcontractors we can call on but a lot are telling us they have enough ‘Boris Money’ to keep them going for a while.

“Some European workers have also gone home while others are picking and choosing when and what work to do.”

The average claim in December was just under £3,500.

A union source said: “There are certainly issues with some European workers not coming back post Brexit and with the Covid travel restrictions.

“But most people in construction want to work and earn their money keeping the sites going.”