It happened on the B3081 near Verwood - he had to be cut free by firefighters.
Dorset Police Sergeant Ordered To Quit
The High Court's ruled that a police sergeant who tried to hide evidence of a dead detective's love affair to protect the other man's long-term partner must quit his job.
The detective had died in a road crash and the sergeant acted to save the dead man's family further grief.
But the misconduct was so serious that it was not enough for Sergeant Neil Salter of Dorset Police to be reduced to the rank of constable, said a judge.
He rejected a tribunal's finding that the public might think it ''harsh and lacking in compassion'' for an officer to lose his job in such circumstances.
Salter, described as an ''old fashioned policeman'' with an unblemished record, was investigating the death of Detective Constable Ian Morton in a road crash in October 2008.
Salter became aware that DC Morton had spent the night before his death with a member of another police force.
Mr Justice Burnett, sitting in London, said the dead man's partner was unaware of the relationship.
Two mobile phones were recovered from the death crash vehicle, one of which Salter knew contained text messages which provided evidence of the affair.
As the deputy senior officer investigating the crash, Salter instructed a police constable to go to a vehicle recovery centre, find the telephone and destroy it.
The officer refused and raised the matter with other senior officers, and Salter was arrested.
When questioned, he admitted using the words ''destroy the phone'' and said he was thinking out loud.
''His intention was to protect DC Morton's family from discovering the other relationship,'' said the judge.
He knew the coroner conducting the inquest into the death would require all the evidence to be produced.
A Dorset Police misconduct panel required him to resign from the force, and the Chief Constable agreed with its decision.
But in July 2010 he won an appeal before the Police Appeals Tribunal after it noted he had not acted for any personal gain but ''to avoid further grief to DC Morton's family''.
The tribunal asked the question:
''If the public was fully informed of the circumstances of this particular case, would it expect or wish the officer to lose his job after 22 years or have him taught a lesson instead?
''The Chief Constable rejects the argument that the public would take a more lenient view than the panel. We are not so sure''.
The tribunal said it was sufficient for Salter to be reduced in rank from sergeant to police constable and allowed to remain in the force.
It noted how a Dorset coroner had described Salter as ''a man of integrity and great loyalty - an old fashioned policeman''.
Describing the phone incident as a ''one-off aberration'' , the panel concluded: ''An officer who has has striven for and achieved a measure of excellence should be entitled to feel that he can meaningfully call upon his record in times of trouble.''
Allowing an application for judicial review filed by the Chief Constable, Mr Justice Burnett disagreed.
He ruled the tribunal had applied the wrong legal test and given too much weight to Salter's ''unblemished career and ''exceptional'' character.
The judge said it was true that the destruction of evidence could arise in worse circumstances than Salter's.
''But his mitigation could not, in my judgment, tips the scales against a sanction that resulted in his leaving the police force.''
The judge used his powers to quash the tribunal's decision and substitute his own decision quashing Salter's appeal - but he gave Salter permission to challenge his own ruling in the Court of Appeal.
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