Malcolm Turnbull has slapped down Tony Abbott and other conservative critics within the party, boldly declaring the political centre ground is the sensible “place to be”.

In a speech delivered to a centre-right think tank in London – but clearly directed toward his detractors at home – Mr Turnbull hit out at conservatives within the Coalition who have repeatedly sniped from the sidelines, criticising his policy approach and the government’s most recent budget as being ‘Labor lite’.

Mr Turnbull said in his speech that the Liberal Party established by Sir Robert Menzies in 1944 was “firmly anchored in the centre of Australian politics”, and was not a party founded necessarily on conservative values.

“Menzies said: ‘We took the name ‘Liberal’ because we were determined to be a progressive party, willing to make experiments, in no sense reactionary but believing in the individual, his right and his enterprise, and rejecting the socialist panacea.

“The sensible centre was the place to be. It remains the place to be.”

Chief among those critics has been former prime minister Mr Abbott, who last month released an alternative policy manifesto for the Coalition and who recently described the May budget as “second best”.

The speech sent shockwaves through conservative politics in Australia, with former Liberal defector Cory Bernardi thanking the Prime Minister for “confirming why regular Aussies need to join” his party.

One Nation leader Pauline Hanson, meanwhile, seized on the comments, branding her party “officially Australia’s largest conservative party”.

Deputy Liberal leader Julie Bishop defended the speech which “eloquently articulates our values”.

Asked if the speech would antagonise colleagues, Ms Bishop told ABC radio: “It shouldn’t.”

“It is a historically accurate articulation of how the Liberal party gained its name.”

New Liberal federal president Nick Greiner also backed Mr Turnbull, while also slapping down Mr Abbott’s conservative agenda – his so-called five-point plan – saying it was “never going to happen” and calling it “politics rather than government”.

Mr Turnbull delivered the speech during his first visit to Britain where he has met British Prime Minister Theresa May who has experienced similar unrest within her own Conservative party.

But Mr Turnbull had a reassuring message for his counterpart, declaring her vision for Britain was “one filled with optimism … it is not a counsel of despair”.

‘Hard not to burst into tears’: Turnbull

Mr Turnbull and Ms May also have met Australian ambulance officers and British police who responded to last month’s terror attack in London.

Mr Turnbull later told Ms May before heading into a Downing Street meeting it was “hard not to burst into tears” as police officers recounted what happened.

“They were very brave men, very brave men and women and I just want to thank them on behalf of all Australians,” he said.

The Borough Market only recently reopened after the June 3 attack, in which eight people were killed and almost 50 wounded.

Malcolm Turnbull with Theresa May at London’s Borough Market where seven people were killed. Photo: Getty

Three terrorists drove a van into pedestrians on London Bridge before abandoning it to run into the popular area, stabbing people with foot-long knives as they went.

The attackers killed South Australian nurse Kirsty Boden and Queenslander Sara Zelenak.

Ms May praised Ms Boden who “rushed to the scene” to help others only to lose her own life.

“They didn’t think of themselves but went to help those who they saw in need.”

The leaders, who have known each other since their Oxford University days, walked through the market, talking to stall holders about the devastating event.

One stall holder booed Ms May as she walked past, saying “they don’t care about us”.

But others were more positive, relating their stories of how terrified people reacted.

As they stood just near where the terrorists were shot dead, some of the vendors described how terrified people reacted.

Mr Turnbull earlier received an intelligence and security briefing from top British officials.

The prime minister and Metropolitan Police commissioner Cressida Dick – Scotland Yard’s first female boss – discussed terrorist attacks in the UK and Melbourne as well as the June 14 Grenfell Tower fire.

At a joint media conference, the two leaders talked up the potential for an Australia-Britain free trade agreement which Mr Turnbull said would be concluded quickly.

“Australians are fleet of foot – we don’t muck around,” he said, adding an EU-Australia deal was also being negotiated.

The UK cannot legally negotiate trade agreements until after exiting the European Union.

Before heading home, Mr Turnbull will also have an audience with the Queen.