The inspectors from the Heath and Safety Executive (HSE) served Prohibition Notices for working unsafely at a height at two of the sites, ordering the dangerous practices to stop immediately.

They also issued one Improvement Notice for training failings at another site and provided written advice for minor safety breaches at the other six.

Common issues found throughout the inspections were that basic precautions were missing, such as edge protection to prevent falls from height, work was not properly planned, site managers were poorly trained and workers had inadequate welfare facilities.

Mike Williams, principal inspector for HSE’s construction division in North and East London said: “Construction remains one of Britain’s most dangerous industries and fatal incidents across London have shown how devastating they can be.

“We are very concerned at the number of small sites that are failing to take the most basic precautions to protect workers and members of the public.

“Good health and safety on construction sites is a legal requirement and we will continue to clamp down on dangerous practices or poor standards until the message gets through,” he added.

Provisional figures published last month by the HSE show 49 fatal injuries to construction workers recorded in 2011/12, compared with 50 deaths in 2010/11.