Commissioner versus the PM: who is in the right?

Sir Paul Stephenson made a thinly veiled attack on David Cameron in his resignation, pointedly stating that Scotland Yard had employed the former News of the World executive Neil Wallis in 2009 at a time when there were no questions about his record, writes Cahal Milmo. In contrast, the Conservative leader had employed the paper's former editor, Andy Coulson, after he had resigned over the phone-hacking affair. Downing Street retorted that its remit did not extend to investigating criminality and therefore different considerations applied. Who is right?

How did the relationship begin?

Cameron & Coulson Mr Coulson was appointed as Mr Cameron's communications director in July 2007 at a time when the then Leader of the Opposition was in need of a more muscular press operation. Mr Cameron had been considering appointing the BBC journalist Guto Harri but was reportedly persuaded by News International's chief executive Rebekah Brooks to consider Mr Coulson. George Osborne, then shadow Chancellor, was keen on the former NOTW editor, believing he had the tabloid instincts to help the Tories win power.

Stephenson & Wallis The official version is that Mr Wallis's company, Chamy Media, won a competitive tender in October 2009 to provide public relations advice to senior Scotland Yard officers. Chamy Media was the lowest-priced contender. Allegations have since emerged that Mr Wallis was invited to apply for the vacancy and favoured because of his links with Mr Coulson. The NOTW executive was also a longstanding acquaintance of senior officers, including Sir Paul.

What work was carried out?

Cameron & Coulson Mr Coulson proved an adept spin doctor, successfully blunting attempts to portray his boss as an Eton-educated toff and revising the image of the Conservatives as "the nasty party".

Stephenson & Wallis Working two days a month at £1,000 per day, Mr Wallis provided "strategic communication advice" to senior officers, including Sir Paul and Assistant Commissioner John Yates.

Was there a potential conflict of interest?

Cameron & Coulson Mr Coulson was a close friend of Ms Brooks and would have played a key role in the Tories' coup of persuading The Sun to switch allegiance to them. Not so much a conflict of interest as Mr Coulson doing his job.

Stephenson & Wallis The Yard took on Mr Wallis at a time when it was facing growing calls to reopen its investigation into phone hacking and offered him a third contract on the same day that credible new allegations were made about the extent of voicemail interception at the NOTW. During his employment, senior Yard officers sought to persuade The Guardian that its investigations into phone hacking were exaggerated. The Yard has said Mr Wallis had no impact on its operational decisions.

Is it a fair comparison?

Sir Paul is right to point out that he has taken responsibility for his force's close relationship with News International in way political leaders have not. But it is difficult to equate the employment by police of a man who held a senior role at a newspaper they were being asked to investigate with No 10's decision to employ an adept tabloid attack dog.