Mr Walker has urged MPs to help him expose further details, saying he could not say more "without incurring a much bigger risk of being sued by the NHS".
"I am still gagged. There's nearly 3,000 pages of evidence of which I have only been able to talk about a few. Those are the things I would like the health committee to expose," he said.
The BBC reported that Mr Walker had been threatened with legal action because of the interview.
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Michael Haines said he wanted to continue his brother's legacy so he would be remembered for his good work rather than his death.
Tomorrow should be a bit quieter in most places, with lighter winds and some lovely winter sunshine.
There will be a widespread frost and ice to watch out for tonight, with some bitterly cold temperatures too.