Policing ganged up on Theresa May and her Brexit-damaged government in a renewed attack on “unforgiveable” actions and “failed policies” that have brought the service to its knees.

National Police Federation chairman John Apter left a Prime Minister-led serious youth violence summit only "cynically optimistic", turning on political leaders for leaving public services "stripped to the bone" and officers "firefighting" when it comes to dealing with crime.

Stepping out from the Downing Street dialogue, the PFEW leader launched a second broadside in as many days on government proposals which could make police, along with teachers and nurses, accountable for failing to spot warning signs that youngsters are becoming involved in knife crime – describing them as a “bit of an insult".

"We already have that level of accountability and we already highlight if we fear that somebody is going down that path," he said.

"My plea is that this cannot be just a talking shop or a photo opportunity.

"It's got to be something meaningful and credible because the country deserves something to come out of this."

Mr Apter, who represents 120,000 rank-and-file officers, said: "While I fully accept we have to look forward, I think the government and the prime minister in particular has to shoulder some of the responsibility for the failed policies.

“What she's done to policing is unforgivable and she's now seeing the impact of that."

And the verbal punishment did not stop there for Mrs May, locked in Cabinet talks in a bid to resolve the Brexit impasse, as newly-installed National Police Chiefs’ Council chairman Martin Hewitt said the additional £970 million funding for policing this year from the government was “not enough to meet all the challenges that the service faces”.

On his first day in the new post, the former Met assistant commissioner said he would be working with the Home Office to make an “evidence-based case for increased investment in the forthcoming government spending review as well as developing ambitious plans to maximise every penny we have”.

More than 100 experts are meeting this week after Home Secretary Sajid Javid floated the idea a month ago of a so-called "public health duty" intended to help spot the warning signs that a young person could be in danger, "such as presenting in A&E with a suspicious injury, to worrying behaviour at school or issues at home".

A consultation in England and Wales – which opened on Monday and runs until May 28 – will assess the extent to which those on the front line will be held to account for failing to prevent a young person getting involved in violence, a Home Office spokesman said.

If passed, new legislation would create a "legal duty" for law enforcement and other agencies, but each "would determine for themselves how they would address and comply" with it, according to consultation papers.

The proposals are similar to the successful approach taken in Scotland, where knife crime has been treated as a public health issue for more than a decade, with a significant reduction in stabbings in Glasgow.

In 2005, after 137 murders in a year in Scotland including 41 in Glasgow alone, a violence reduction unit was set up by Strathclyde Police.

The following year, the VRU became a national unit and it has continued, with a current annual budget of around £1 million, to back a wide variety of initiatives. These include offering young people at risk of being drawn into violent crime, or who already have convictions, alternatives such as training, jobs and youth clubs.

There are also schemes that support parents, aim to reduce domestic violence – a key cause for children who go on to commit violent crime – and tackle alcohol abuse.

London has its own violence reduction unit – bringing together the Met Police, health workers and staff from local councils, and Home Secretary Sajid Javid behind the public health approach nationally.

Others have also suggested the ‘public heath safety’ proposals could put greater pressure on frontline staff.

Royal College of Nursing acting chief executive and general secretary Dame Donna Kinnair said: "With almost 40,000 nursing vacancies in England alone, nurses are already concerned about providing safe and effective care with such widespread staff shortages.”

Dr Mary Bousted, joint general secretary of the National Education Union, said: "Neither the blame for or the solution to violent crime can be laid at the door of schools or frontline hospital staff.

"Schools already have strong safeguarding practices in place and staff will be alerted to any issues of concern. The problem is what happens after issues of concern have been identified.

"Schools have lost pastoral support, special needs teachers and school counsellors."

Opening the serious youth violence summit on Monday, Mrs May said: "We cannot simply arrest ourselves out of the country's knife crime crisis.

"This is a wider problem, it is more deep-seated and we have to have a more coordinated effort."

The Prime Minister met with the families of knife crime victims as well as experts including Met Police Commissioner Cressida Dick, Patrick Green from the Ben Kinsella Trust, and Baroness Newlove, the Victims' Commissioner for England and Wales, whose husband Garry was beaten to death by a gang vandalising his car in 2007.

It is just 48 hours since the Home Secretary granted forces new powers to increase stop and search activity following a spate of bloodshed across London and the rest of England since the start of 2019.

"Violent crime is like a disease rotting our society and it's essential that all public bodies work together to treat the root causes," he said.

"The public health, multi-agency approach has a proven track record and I'm confident that making it a legal duty will help stop this senseless violence and create long-term change."

And it follows in the wake of a spate of unprecedented incidents with six deaths and 10 injuries in the last few days across the UK.

There were 285 homicides where the method of killing was by a knife or sharp instrument in the year to March 2018 – the highest number since records started in 1946.

Mrs May came under fire last month after she suggested that police cuts were not to blame for a spate of fatal stabbings on teenagers.

Senior figures in policing were at odds with the Prime Minister as they called for a reverse to slashes in staffing levels.