Rescue crews spent much of yesterday morning battling to save the man trapped in the submerged cab in a large drainage channel in Mepal.
Fire fighters wearing dry suits managed to smash the glass of the cabin and pulled the man’s head and shoulders above the water though his feet remained trapped and he died before he could be released.
The driver had been working to dredge a frozen section of the Old Bedford River for the Environment Agency.
Julian Fountain, incident commander for Cambridgeshire Fire and Rescue Service, said: “All agencies have worked extremely closely together to make every effort to fully release the man from the water as quickly as possible.
“However, due to the location of the crane, the freezing weather conditions and the fact that the man was trapped, this could not happen in time.”
The Environment Agency, which said it had been carrying out de-silting work along the river, said it would mount an internal inquiry and co-operate with a Health and Safety Executive investigation.
“Everyone at the Environment Agency is extremely upset by today’s tragic incident,” said area manager Geoff Brighty.
“All our thoughts and sympathies are with our colleague’s family and friends.”