Dangerous working practices have been identified at a dozen firms carrying out property development and refurbishment projects in Waltham Forest.

During a crackdown by the Health and Safety Executive (HSE), inspectors visited 16 sites and ordered that all work should be stopped on no fewer than 12 of them.

Unsafe working practices including unsafe structures, fire risks, a lack of competent workers and unsafe excavations were identified at the sites, which were then served with prohibition notices.

The notices mean that all work must be stopped with immediate effect due to serious risk of injury.

Inspectors also served five improvement notices on the owners of the buildings and on the contractors involved, ordering safety standards to be improved.

The failure of a firm to comply with the notices would be a criminal offence.

HSE inspector Sarah Snelling said: “We have been working with local authority officers in this area for several months and have been appalled at the willingness of building owners and their contractors to ignore basic safety precautions.

“They are risking the lives of those working on these sites as well as others in the immediate area.”

The HSE has not released the names of the firms on which they served the notices as they have the right to appeal the decision.

Under current guidelines, they may be given a period of up to three weeks to prove the allegations against them are unfounded.