Janice Reed was pregnant with David Wilkie's second child when he died after two striking miners threw a concrete block from a bridge onto his car.

Pontypridd MP Mr Howells - who worked for the National Union of Mineworkers (NUM) at the time - recently admitted that he panicked following the death and shredded historic documents. Police are investigating the claims.

The now Transport Minister has denied that the information was of any relevance to the killing.

Mr Wilkie, who was living in Treforest at the time, was taking one of the few strike-breakers in south Wales back to work at the Merthyr Vale colliery.

He was killed when two young miners dropped a concrete block off a road bridge onto his car.

The pair were later jailed for murder but this was reduced to manslaughter on appeal and they served five years in jail.

Following the death Mr Howells destroyed historic documents at the south Wales strike headquarters in Pontypridd.

Speaking on BBC Wales documentary The Coal War for the first time in 20 years, Mrs Reed questioned his motives for getting rid of the NUM information - posing the simple question: "Why?"

But during the programme Mr Howells said he had "nothing to hide."

Its presenter and BBC Wales Political Editor David Williams said her continuing quest for information surrounding the death of her husband illustrated "just how deep the wounds run."

"David Wilkes' death came to symbolise the desperation of men consumed by frustration and hardship," he said.

"It is the most vivid, if not the most poignant, memory of the deep hurt caused in that exhausting 12 months."

The Coal War will be broadcast on Monday at 2235 GMT on BBC 1 Wales.