The new regime involves workers giving a thumbs up sign to plant operators, asking permission to enter their work zone.

Returning the simple gesture means operators are aware of workers in the vicinity of their machines allowing them to take extra care.

Thames Water is adopting the practice on its civils sites.

The utility giant’s site literature states: “The ‘thumbs-up’ is a universal symbol that something is OK.

“It crosses all languages and can be understood over the loudest of noises – that’s why fighter pilots use it before they take off, and that’s exactly why we want to adopt it in our world.”

Bam Nuttall, Carillion and the Buckingham Group are also using the scheme on their sites.

Lynch director Rob Lynch said the idea came to him during one of the firm’s regular toolbox talks.

He said: “I just asked the team to give me the thumbs-up if they understood a point i was making and it seemed such an easy gesture which can make a big difference.

“Everyone understands what you mean and it only takes a few seconds to give the thumbs-up and see that a plant operator has seen you when they signal back.”