Judge Ronald Moss at Luton Crown Court was said to be in a state of "complete disbelief" after being told Pc Craig Birch could not be contacted.

He said: "A trial of dangerous driving should have gone ahead except one of the police officers is in Spain."

The nine men and five women from which the jury would be chosen laughed.

Prosecutor Thomas Quinton said Pc Craig Birch had not left any contact details and no evidence against the driver would be offered.

What if this had been a charge of grievous bodily harm or rape or something like that? Judge Ronald Moss

Cyril Mitchell, 34, from Luton, Beds, was told he was free to leave.

Judge Moss said: "Though dangerous driving is serious, what if this had been a charge of grievous bodily harm or rape or something like that?"

A spokesperson for Bedfordshire police said: "We notified the Crown Prosecution Service (CPS) in early July that we do not know where Pc Birch is living now and would not be able to attend.

"The CPS have known this for two months and it was assumed they would make other arrangements."

Judge Moss was told by prosecutor Thomas Quinton that the information had arrived with the CPS in "dribs and drabs".

He said they were only told on Wednesday night that the officer could not be found.

Mr Quinton said the CPS had tried to alert the court to remove the case from the list, but it was too late.