The firm’s Cambridge depot received a call to book six excavators and a dumper for delivery to site.

The hire appeared to be a genuine order from an existing construction customer who has an account.

H.E.Services hire manager Adrian Holmes said: “They even sent us through an official order from the regular person who hires in plant and equipment.”

But recently introduced cross checks by the firm flagged the order as suspicious despite the convincing details.

Upon delivery to site near Amersham in Buckinghamshire last Friday the ‘hirer’ was waiting to receive the plant but as it was being unloaded Thames Valley Police swooped.

Those arrested were later released on police bail and the investigation is on-going.

H.E. Services beefed-up its security following a swathe of thefts in the  South East of England over the last six months often by people posing as genuine customers.