POLICE deliberately destroyed witness statements relating to striking building workers the Shrewsbury 24 in the 1970s because they were taken “before officers knew what they were trying to prove,” the Court of Appeal was told today.

And “higher echelons of the state” were involved in production of a “deeply prejudicial” TV programme which was broadcast during the first of the trials in 1973, the court was told.

The trials resulted in convictions of the 24 on charges including conspiracy to intimidate, unlawful assembly and affray.

Six people — Des Warren, Ricky Tomlinson, John McKinsie Jones, Brian Williams, Arthur Murray and Mike Pierce — were sent to prison for periods ranging from three years to six months. Others suffered lesser sentences.

Almost 50 years after the 1972 strike, in which building workers campaigned for better pay and an end to horrific and unsafe working conditions, lawyers representing 14 of the Shrewsbury 24 are arguing for their convictions to be quashed.

Danny Friedman QC, representing 12 of the pickets, told the court that because the defence was not told about the destruction of original witness statements, the pickets were “manifestly prejudiced by not being able to seek to investigate these matters before the jury.”

He said the prosecution was aware that original statements had been destroyed two weeks before the beginning of the first of the three trials, but did not tell the defence.

In a note of a meeting between investigating officers and the prosecution, the police said the original statements had been taken “before officers knew what they were trying to prove,” Mr Friedman said.

Mr Friedman concluded that “there has undoubtedly been material non-disclosure of the fact that statements were destroyed” which he argued rendered the convictions unsafe.

No arrests were made on the day of the picketing, he said. Police took action after “a period of concerted lobbying by the National Federation of Building Trades Employers,” which compiled an “intimidation dossier” that was sent to the then-home secretary Robert Carr.

Mr Friedman said there had been “covert” state involvement in the production of a TV documentary, “Red Under The Bed,” which was broadcast during the first jury trial in 1973.

A live panel discussion which followed the programme featured a Conservative MP describing the strike as an example of “blatant communist influence,” which would have been “deeply prejudicial, provoking panic in the mind of this Shrewsbury jury.”

The court was told that a “covert Foreign Office agency” known as the Information Research Department (IRD) provided “considerable assistance” in making Red Under The Bed.

Mr Friedman said in written submissions that the head of the IRD had told a senior Foreign Office official that “we had a discreet but considerable hand in the programme.”

He said the IRD “had consulted the Security Service” — also known as MI5 — about the show, which was also praised by then-prime minister Edward Heath who said: “We want as much as possible of this.”

Mr Friedman told the court: “It is obvious … a covert executive agency played a part in deliberately propagandising against the core subject matter of the proceedings.

“It is clear now that the higher echelons of the state bore responsibility for deliberate covert involvement in the production of the programme.

“In all the circumstances, the approach taken to broadcasting this programme has rendered the convictions unsafe.”

John Price QC, representing the Crown Prosecution Service, said the deliberate destruction of witness statements “was not done for an improper purpose.”

He said there was “no destruction of evidence, only of form.”

He said there was no link between the broadcasting of the Red Under The Bed TV documentary and the trial, and said the judge “had already directed the jury in strong terms that political considerations of any kind were irrelevant.”

The hearing continues today.