The alert advises hirers and owners that simple covers over operator controls are not sufficient precaution against crushing when working below fixed structures like steelwork and roofing.

In five of the accidents to be placed under scrutiny the operator was crushed between an overhead obstruction and a cover or shroud fitted over the controls of the machine.

They died either from crush injuries or asphyxiation, often after falling onto controls and being pinned between an overhead obstruction.

HSE officials have concluded that secondary anti-crush bars or pressure sensing devices should be fitted to MEWPS when there is a risk the operator could be crushed by an uncontrolled operation.

Skanska was the first UK contractor to ban use of cherrypickers without anit-crush bars on its sites back in 2012.

Secondary guarding options

International Powered Access Federation, IPAF published a document outlining currently available devices to help protect against entrapment/crushing injuries on mewps cited by HSE