Construction inspectors will be focusing on sites in Kensington and Chelsea, and Hammersmith and Fulham.

The move follows a number a number of fatal incidents, as well as serious injuries, in the capital in recent years relating to basement projects.

Over the last 10 years, HSE has received reports of 17 construction workers having died as a result of an excavation collapsing, whilst in the same period 27 were seriously injured.

In December 2014, following the death of a labourer in a basement excavation collapse in Fulham, a company director was found guilty of manslaughter offences and jailed.

Inspection teams will be looking at key safety issues including collapsing excavations; risk of building collapse from structural alterations or undermining by excavating; the dangers of handling heavy steel beams; poor access and risks of open or unprotected parts of sites.

HSE construction inspector James Hickman said: “The construction of basements in London is increasingly widespread. Often it is carried out under existing homes as owners seek to increase their living space without a house move.

“The work is technically challenging and can carry substantial risk. Standards are often poor and often vulnerable sections of the labour market are recruited.

“Contractors are failing to appoint a competent temporary works engineer to design suitable propping to support excavations and existing structures.

“Likewise, on many projects basic safeguards are missing, such as edge protection to prevent falls from height. And all too often little thought is given to providing proper welfare facilities for site workers.

“Where we find poor practice that is putting lives at risk we will take action, including stopping work and prosecuting those responsible.”