Director of BBC Northern Ireland Peter Johnston confirmed he was involved in decisions relating to the Newsnight investigation that wrongly linked a senior Conservative politician to child sex abuse in north Wales.

An inquiry into the programme, conducted by Director of BBC Scotland Ken MacQuarrie, found "unacceptable failings" by the corporation.

Mr Johnston - who is on the BBC's national management board - has said he is not considering his position and is awaiting further details of the investigation.

Senior BBC employees are facing the prospect of disciplinary action after the corporation admitted the Newsnight programme, which mistakenly implicated Robert McAlpine in a child sex abuse scandal, failed to complete "basic journalistic checks".

It comes as British Prime Minister David Cameron and Culture Secretary Maria Miller added their voices to growing criticism over the £450,000 (€560,000) pay-off given to former director-general George Entwistle, calling it "hard to justify".

Mr Entwistle, who resigned on Saturday, has been awarded a full year's pay after bowing out 54 days into his reign, despite normally being entitled to only half that figure.

BBC Trust chairman Lord Patten yesterday defended the sum, saying it was "justified and necessary" to allow a clean break and avoid lengthy delays.

The settlement was discussed in Westminster on a further day of drama, which saw two senior figures - BBC director of news Helen Boaden and her deputy Stephen Mitchell - step aside from their posts temporarily.

Last night, the official report into the botched Newsnight programme by Mr MacQuarrie found there was confusion about who had the ultimate responsibility for "final editorial sign-off" on the story that falsely linked Mr McAlpine to a paedophile ring.

In the report, he said the programme's editorial management structure had been "seriously weakened" as a result of the editor having to step aside over the Jimmy Savile scandal, and the departure of the deputy editor.

Mr MacQuarrie added that there were shortcomings in the quality of the journalism.

He said: "During the editorial decision-making process, some of the basic journalistic checks were not completed.

"Specifically, identification was not confirmed by photograph with the first victim. The second victim could not be traced in order to provide up-to-date corroboration."

Although legal advice was sought over the report, no right of reply was offered to the unnamed individual at the centre of the allegation.

The programme featured an interview with Steve Messham, an abuse victim who said a senior political figure of the time abused him. He later said he wrongly identified his abuser and apologised.