A man arrested as part of the Scotland Yard investigation into phone hacking at the News of the World gave advice to the University of East Anglia over the Climategate affair.

Neil Wallis, managing director of consumer agency the Outside Organisation and former News of the World executive editor, became the ninth person to be arrested in connection with the scandal on Thursday.

The 60-year-old, who was deputy editor under Andy Coulson's editorship, was detained in a dawn raid on his west London home and questioned for several hours at Hammersmith police station.

The EDP has discovered that Wallis, who joined Outside Organisation in October 2009 as a senior consultant, was used by the UEA following the Climategate scandal which broke out in 2009 following the leak of thousands of emails which climate change sceptics claimed showed data had been manipulated in favour of man-made climate change.

A UEA spokesman confirmed Wallis did give them advice following the scandal which last year saw Phil Jones, director of the Climatic Research Unit cleared by a committee of MPs of hiding or manipulating data to back up his own science.

The revelation came on another extraordinary day in the phone hacking scandal as Rebekah Brooks finally resigned as chief executive of News International amid growing political and commercial pressure on the company and owner Rupert Murdoch prepared to use adverts in national newspapers today to apologise for the NoW's 'serious wrongdoing'.

The UEA spokesman said: 'The vice-chancellor sought communications advice from a large PR company following the unauthorised publication of emails from the Climatic Research Unit. The company assigned Neil Wallis to us for this purpose.'

Last March Phil Willis, chairman of the commons science and technology committee, said there was no case to answer following accusations of dishonesty levied at Prof Jones.

There have been several reviews, and a police investigation, into the saga, which began weeks before the important Copenhagen Climate Change Conference.

The committee's largely positive findings were welcomed by the UEA, and Edward Acton, vice-chancellor, said: 'We are delighted that the select committee has produced a fair and balanced report that makes crystal-clear that the scientific reputation of Prof Jones and Cru remains intact''.

Wallis, who is understood to have been released on bail until October, was arrested on suspicion of conspiring to intercept communications, contrary to section 1(1) Criminal Law Act 1977.

He is no longer listed as the agency's MD on Outside Organisation's website. Instead, the site states: 'Neil became a freelance media consultant to Outside in 2009.'

Outside's website has also deleted a portion of Wallis' biography that read: 'What he [Wallis] doesn't know about journalism and media isn't worth knowing.'

Following his arrest it also emerged that Scotland Yard had paid Wallis �24,000 to work as a two-day-a-month public relations consultant.

His contract was cancelled less than six months before the Operation Weeting investigation into phone hacking was launched.

Home secretary Theresa May has written to Metropolitan Police Commissioner Sir Paul Stephenson to demand an explanation, while the commissioner, who will now give evidence to the Commons Home Committee looking into the police investigation, was also summoned for a 'very frank discussion' with London Mayor Boris Johnson.