BRITAIN'S most senior police officer suddenly resigned last night over the News of the World phone-hacking scandal – just hours after former News International chief executive Rebekah Brooks was arrested.

Sir Paul Stephenson, the Commissioner of the Metropolitan Police, stepped down after he was linked yesterday to free stays at a health resort which employed the newspaper’s former deputy editor Neil Wallis as a public relations guru. Wallis was arrested last week.

Sir Paul, 56, said: “I may wish we had done some things differently, but I will not lose sleep over my personal integrity.”

Mrs Brooks, 43, was arrested after she attended an appointment with Metropolitan Police officers from Operation Weeting, the inquiry into phone hacking including that of murder victim Milly Dowler’s phone.

She remained in custody last night after being held over the inquiry into hacking by journalists during her time as editor.

However, her spokesman questioned whether it would be proper for her to be grilled by MPs on the Commons Culture, Media and Sport Committee tomorrow. She is due to face questions along with News Corp owner Rupert Murdoch, and his son, James, the chairman of News International, over the scandal.

Mrs Brooks, her spokesman said, was taken by surprise, as last week it had been indicated to her she was not on the police “radar.”

He added: “She was going, anticipating to help with their inquiry. She wasn’t anticipating she was going to be arrested. It has many implications for Tuesday.

“Over the next 24 to 36 hours her lawyers will have discussions with the select committee to see if it will still be appropriate [to attend]. She certainly wants to. It adds another layer of complexity.”

Labour MP Chris Bryant questioned whether her arrest was a “ruse” before the meeting. He added: “It is unusual to arrest by appointment on a Sunday and that just makes me wonder whether this is some ruse to avoid answering questions properly on Tuesday in the Commons committee.

“I don’t want to overstress that argument but it’s unusual to be arrested on Sunday by appointment -- why couldn’t that have happened tomorrow or Wednesday or whenever?”

In his resignation speech Sir Paul said the UK’s biggest force could not afford “any doubts” about its head.

It came hours after a Sunday newspaper revealed he enjoyed £12,000 worth of hospitality at Champney’s health resort in Tring, Hertfordshire, whose public relations is handled by Mr Wallis.

Denying any impropriety, Sir Paul said: “I have heard suggestions that we must have suspected the alleged involvement of Mr Wallis in phone hacking.

“Let me say unequivocally that I did not and had no reason to have done so.”

Prime Minister David Cameron said: “I respect and understand his decision to leave the Met.

“What matters most of all now is that the Metropolitan Police and the Metropolitan Police Authority do everything possible to ensure the investigations into phone hacking and alleged police corruption proceed with all speed, with full public confidence and with all the necessary leadership and resources to bring them to an effective conclusion.”

But Shadow Home Secretary Yvette Cooper contrasted Sir Paul’s relationship with Mr Wallis and Mr Cameron’s with Andy Coulson, the former News of the World editor who resigned over the the scandal before he briefly became No 10’s director of communications.

She said: “It is striking that Sir Paul has taken responsibility and answered questions about the appointment of the deputy editor of the News of the World, whereas the Prime Minister still refuses to recognise his misjudgment and answer questions on the appointment of the editor of the News of the World at the time of the initial phone hacking investigation.

“People will wonder at why different rules apply.”

Last week, Sir Paul was criticised by the London Mayor Boris Johnson over his dealings with Mr Wallis, 60. The former newspaper executive enjoyed a two-days-a-week contract as consultant to the Metropolitan Police for £1000 per day. He also dined with Sir Paul in 2006, during the inquiry’s initial phase.

Meanwhile, Labour leader Ed Miliband called for an overhaul of media ownership rules that would reduce Murdoch’s UK market share and prevent the “abuses of power” that led to the current scandal.