Fortunately, the Volkswagen Caravelle had no passengers aboard as it was on its way to pick up a fare – but it was scant consolation for the red-faced driver who had to call the taxi office for help after getting stuck in the soft river bed.

Business owners Keith Jarvis and Pat Bowles took along a towrope, expecting to find the eight-seater minibus just off the ford between the village and South Acre.

But Mr Jarvis said: "It took ages to find him and we couldn't believe it when we saw where he was – it was several hundred yards along the river!

"The vehicle still had its engine running and headlights on, and he was sitting in it with his trousers rolled up round his knees. I shone a torch in the river and there were fish swimming around the headlights."

Mrs Bowles said: "The driver told us he was following his sat nav and when it told him to carry straight on he did, even though it was taking him along the river!"

As it was nearly midnight, the minibus remained in the Nar overnight and a local farmer with a tractor towed it out on Sunday. It was returned to Lynn on a low-loader to be checked over.

Yesterday, the owners, who have denied plans to start a water taxi business, said the driver, a Lynn man, was too embarrassed to talk about his experience.

"It's the talk of the taxi ranks today and the drivers keep texting each other jokes about it," Mr Jarvis said.