Former Conservative MP Rory Stewart hopes to oust Labour incumbent Sadiq Khan when Londoners go to the polls to decide their mayor for the next four years on May 7.

Stewart made headlines last year during his attempt to replace ex-Prime Minister Theresa May as leader of the Conservatives.

After losing out to Boris Johnson, he subsequently lost the the Tory whip "via text message" with 20 other MPs after voting against the Johnson administration to minimize the risk of a No-Deal Brexit.

Now running as an independent, Stewart is hoping to channel his ministerial background if elected as London's next mayor.

"A lot of my experience is around security," he said.

"As Minister of State for Prisons I had the job of turning around violence in prisons, which had tripled in five years, and I put my job on the line to reduce it.

"In a system where many people thought crime couldn't be reduced, we reduced violence by 16 per cent in seven months, so I think that's the first really important part of what I bring," Stewart added.

Most of Stewart's rivals in the mayoral election frequently tout their London credentials.

Khan, for example, grew up on a housing estate in Earlsfield, while Tory candidate Shaun Baily was raised in North Kensington.

The former MP for Penrith and the Border's own upbringing was the other side of the neighbourhood.

"I grew up in South Ken," Stewart pointed out.

"I'm still living in the same house in London I lived in when I was a small child.

"I still have the same GP that I have 46 years ago. I'm a very deep Londoner.

"My mother grew up in Wimbledon my grandfather was a Wimbledon GP so I'm deeply embedded in London, and my little boy is at a London school and my other little boy is at a London nursery," he added.

A former prisons minister, Stewart is laser-focused on security as central to his campaign.

He said he accepts that there is a strong link between poverty and violent crime but caveated that more could be done in the short term to bring the violence down.

"Of course there is a link between poverty and violent crime in London but that doesn't mean that there is no solution or way of bringing it down in the short term," Stewart said.

"For example it was very important for me to understand that many of the people in prisons come from very poor and difficult backgrounds and that we need to be doing things to address the root causes of it.

"But that doesn't mean that the only way of reducing violence in prisons was addressing those root causes. There are things you can do immediately," he said.

Part of Stewart's plan to do this focuses on devolving policing to a greater extent in London, focusing at the borough and even the ward level.

That goes for a number of existing police tactics including the controversial Stop and Search policy.

"The question with Stop and Search is how you do it," Stewart said.

"The right place and the right time of course it's a very powerful weapon in the police's armoury.

"The way to make it work is to have the right neighbourhood presence on our streets.

"That means having uniformed officers who really know their communities well. That way they're doing it, they know who they're stop and searching and it's for a purpose.

"What doesn't work is to try to do it without the proper neighbourhood structure in place," he added.

Stewart said he would "make sure" that every ward in London had a sergeant, two police constables and three PCSOs if elected mayor.

"Whose job would be to get to know as many of the residents as possible so they know what's happening when they go into those estates," he added.

When asked whether he would match Khan's promise to boost police funding in London by £234 million, Stewart said "yes", and questioned where the extra funding had been previously.

"Why didn't he do that before? He spent four years blaming the central government saying he doesn't have any money and then suddenly yippee-do he finds a pot of gold just before an election.

"I would say that it is my responsibility to reduce violent crime. Have you every heard him do that?

"If I'm in charge those new officers will go into the neighbourhoods," Stewart said.

"This is never just about resources. It's about actions, the way you do things."