Image copyright Reuters Image caption Jodie Chesney was killed in a stabbing in an east London park as she played music with friends

Police have been promised an extra £100m by the government to help them tackle a knife crime "epidemic" in England and Wales.

The money will mainly go to the seven forces where violence is highest.

But the fund - announced by Chancellor Philip Hammond in his Spring Statement - falls short of the £200m to £300m requested by police chiefs last week.

London Mayor Sadiq Khan said the extra money was "a drop in the ocean" after years of decreasing police budgets.

"Cuts have consequences and the government needs to urgently give our police the funding they desperately need," he said.

Funding to police forces - which comes from central government and council tax - fell by 19% in real terms between 2010-11 and 2018-19, according to the National Audit Office.

Officer numbers have fallen by around 20,000 since 2010.

Mr Hammond initially said police forces must use their existing budgets to tackle knife crime, following requests from senior officers.

The National Police Chiefs Council (NPCC) welcomed the new money, saying it would boost the number of officers patrolling crime hotspots, increase the use of stop and search, and help to disrupt criminal gangs.

The funding would also be used to fund Violence Reduction Units that seek to tackle the underlying causes of violent crime.

The chancellor's announcement follows a spate of fatal teenage stabbings, with two 17-year-olds killed in separate knife attacks in London and Greater Manchester earlier this month.

Jodie Chesney was killed in an east London park as she played music with friends, and Yousef Ghaleb Makki was stabbed to death in the village of Hale Barns, near Altrincham.

Mr Hammond told the Commons a "wider, cross-agency response to this epidemic" was required.

"Action is needed now. So the prime minister and I have decided exceptionally, to make available immediately to police forces in England an additional £100m," he said.

Image caption Yousef Makki and Jodie Chesney, both 17, were killed in separate knife attacks two days apart

The money is for one year, with a longer-term funding settlement for the police expected to form part of the Spending Review.

Home Secretary Sajid Javid tweeted: "It's vital police have the resources they need to crack down on the rising levels of knife crime.

"I've listened and we will be giving £100m extra to forces, targeting the hardest hit areas. I'll continue to give police the support they need."

The BBC's political editor Laura Kuenssberg described the funding as a "political win" for Mr Javid, who has previously said police chiefs should be "listened to".

The forces that will mainly benefit from the new funding are: Metropolitan Police, West Midlands Police, Greater Manchester Police, Merseyside Police, South Yorkshire Police, West Yorkshire Police and South Wales Police.

While 80% of the money is new Treasury funding, 20% is from the Home Office's "re-prioritisation" of funds.

The funding announcement comes after the government in December pledged £161m for police forces, saying it would protect police budgets in "real terms".

It also said police and crime commissioners would be able to raise additional funds by increasing council tax.

Both changes are due to come into effect in April.

NPCC chief constable Sara Thornton said of the extra £100m being promised: "The additional government funding announced today is very welcome. It will help police forces strengthen our immediate response to knife crime and serious violence.

"Bringing violence down is a police priority."

She said all forces across England and Wales were undertaking a week-long intensive operation to tackle knife crime, including test purchasing weapons from shops, weapons sweeps and speaking to young people about the dangers of knives.

Total knife offences in England and Wales Offences involving a knife or sharp instrument

Chair of the Police Federation of England and Wales, John Apter, welcomed the additional funding, but said it was "just a short-term fix".

"It is a sad state of affairs when the home secretary has to take a begging bowl to the Treasury in a bid to solve the crisis we find ourselves in," he said.

"The government must make a significant investment in the spending review to give police the long-term boost they need."

The new funding comes after the Metropolitan Police Commissioner Cressida Dick said there was "obviously" a link between violent crime and falling police numbers.

However, Mrs May insisted there was "no direct correlation".

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