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.
More top news
A suspected burglar and domestic abuser who goaded police on their own Facebook page has been taunted back after handing himself in.
Motorists are to be allowed 10 minutes' grace after a parking ticket runs out before they can receive a fine, under new rules.
Billionaire Microsoft co-founder Paul Allen has claimed discovery of the Japanese battleship Musashi that was sunk by the US Navy in 1945.