The former News of the World chief reporter Neville Thurlbeck has threatened to blow the lid on the phone-hacking scandal, promising that the "truth will out" and "those responsible will eventually be revealed".

In a clear shot across his former employers' bows, Thurlbeck said that there was "much I could have said publicly to the detriment of News International". It was his first public statement since he was arrested and bailed for alleged phone hacking in April.

The 49-year-old ex-chief reporter at the now defunct NoW was sacked by Rupert Murdoch's News International last month, prompting him to sue his former employer for unfair dismissal. Thurlbeck had applied for "interim relief" at an employment tribunal hearing scheduled to be heard on Friday but pulled out late on Thursday.

His solicitor Nathan Donaldson, employment partner at DWF, issued a statement confirming that Thurlbeck was continuing his action against News Group Newspapers, the NI subsidiary that published the News of the World, for unfair dismissal and whistleblowing.

"Scotland Yard has now made me aware of the reason for my dismissal, a reason which News International has withheld from me for almost a month," Thurlbeck said in a statement issued by his solicitors. "For legal reasons, I am unable to go into the reason cited. However, I will say this: I took no part in the matter which has led to my dismissal after 21 years of service.

"I say this most emphatically and with certainty and confidence that the allegation which led to my dismissal will eventually be shown to be false. And those responsible for the action, for which I have been unfairly dismissed, will eventually be revealed."

Thurlbeck also claimed that for more than two years, News International had accepted he was not responsible for the matter in question and there was "no valid or reliable evidence now to support their sudden volte face".

He added: "At the length, truth will out."

Thurlbeck also said he would "fight my case to the end" and accused News International of "giving off the record briefings" to the press.

"This has compelled me to speak for the first time since my name became linked to the phone-hacking scandal through the 'For Neville' email more than two years ago," he said.

"I would request that News International abandon the unseemly practice of whispering behind the back of a loyal and long-serving former employee.

"There is much I could have said publicly to the detriment of News International but so far, have chosen not to do so."

News International said in a statement that it was "not able to comment on circumstances regarding any individual". It added: "As we have said previously, News International continues to co-operate fully with the Metropolitan police service in its investigations into phone hacking and police payments to ensure that those responsible for criminal acts are brought to justice."

The Guardian revealed more than two years ago the existence of a "For Neville" email – believed to be a reference to Thurlbeck – sent by private investigator Glenn Mulcaire, which contained a transcript of messages left on a mobile phone belonging to the Professional Footballers Association chief executive, Gordon Taylor. The "For Neville" email contradicted the defence that News International had maintained until late 2010, that phone hacking was limited to Mulcaire and one "rogue reporter" on the News of the World, former royal editor Clive Goodman. Both were jailed in early 2007 for phone-hacking offences.

Thurlbeck was due to attend an interim relief hearing about his unfair dismissal claim, but withdrew because the "issues to be determined by the employment tribunal will require key individuals within the News Group Newspapers being cross-examined".

His solicitors added that "unfortunately" Friday's hearing had been limited to a review of papers and because of this procedural limitation Thurlbeck and his legal team decided to withdraw. They wanted to ensure the benefits of a full hearing where complete disclosure from the parties would be made.

NI's parent company, News Corporation, set up an internal investigation unit, the management and standards committee, on the orders of Rupert Murdoch in the summer to assist the police's phone-hacking investigation and purge the organisation of bad practices.

It is understood NI is not telling former employees why they are being dismissed under the MSC's rigid clean-up protocol, which aims to ensure that any potential police investigation is not compromised.

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