A POLICE chief says investigators 'really hope' that missing Sarah Everard is still alive, following the arrest of a police officer over her disappearance.

The 33-year-old woman from York, who is a former Fulford School pupil, has been missing since disappearing last Wednesday evening while walking home to Brixton from Clapham, in south London.

A serving Metropolitan Police officer has been arrested in connection with her disappearance in what the force has called “a serious and significant development."

The officer was not on duty at the time of Sarah’s disappearance.

Speaking to journalists outside Scotland Yard this morning, Assistant Commissioner Nick Ephgrave said investigators “really hope” that the 33-year-old is still alive.

He said detectives were working “at all speed” to find out what had happened to Ms Everard, and repeated appeals for members of the public to come forward with information.

Turning to her York family, who include University of York professor Jeremy Everard, he said: “As a father myself of four young women I can only imagine the anguish that Sarah’s family are feeling at this very very difficult time.”

In an unusual step, the force has not revealed what the officer has been arrested for, and Mr Ephgrave would not say whether they know Sarah.

The officer was arrested yesterday evening at an address in Kent, along with a woman who has been held on suspicion of assisting an offender.

Ms Everard is thought to have walked through Clapham Common towards her house in Brixton – a journey which should have taken around 50 minutes.

She was last captured on a doorbell camera walking along the A205 Poynders Road towards Tulse Hill at around 9.30pm on March 3.

On Tuesday evening, police put up a cordon outside a block of flats near where the footage was recorded.

The search was focused on the Poynders Court housing complex on Poynders Road, and forensics officers could be seen examining the area.

Sniffer dogs were also used to search the nearby Oaklands Estate and gardens in surrounding streets, while other officers were lifting covers and searching drains along the A205.

The Met said it had received more than 120 calls from the public and had visited 750 homes in the area as part of the investigation.

Mayor of London Sadiq Khan told the PA news agency: “First and foremost I think all of our thoughts would be with Sarah’s family, her parents and her siblings and her friends.

“It must be awful for them, they are in our thoughts and prayers. Actually Sarah went missing from near to where I live and we’ve seen, my wife and daughters walking around, the posters her friends have put up and it’s heart-breaking, it’s heart-wrenching.”

He said he was in regular contact with the Met Commissioner Dame Cressida Dick about the investigation.

Mr Khan added: “It is now in the public domain that a serving Met Police officer has been arrested.

“One of the things that this confirms that actually our police service, when it comes to keeping the public safe, when it comes to investigating crime, they work in a situation that is without fear or favour. They will follow the investigation to wherever it takes.”