The Mayors of London and Manchester have joined forces in a bid to prevent further police funding cuts.
In a letter to the Chancellor, the Mayors urged him to "put public safety first" and demanded an end to the real-terms cuts to policing budgets since 2010.
This year, both London and Manchester have suffered horrific terrorist attacks, with the police response being dubbed "phenomenal" by the two public figures.
However, as counter-terrorism experts warn the number of attacks and attempted attacks will continue to increase, the Mayors said they are "extremely concerned" about the police's ability to keep the cities safe.
With an increase also in the amount of overall crime and violent crime across the country, the pair said the police's ability to respond is being "put at risk by the funding crisis".
Writing to the Chancellor on Tuesday (November 14), the Mayor of London Sadiq Khan and the Mayor of Greater Manchester Andy Burnham urged Mr Hammond to act.
"We are extremely worried that the police's ability to keep our cities safe, and to prevent and respond to the risk of future terrorist attacks, is being put in jeopardy by the current funding crisis," they said.
"As you know, counter-terrorism experts are warning that the increase in attacks and attempted attacks this year is not a blip, but a sustained rise.
"And this is against the backdrop of crime rising across the country and violent crime rising even faster."
In London, Metropolitan Police has had to make £600 million of cuts since 2010, and must find a further £400 million of savings by 2021.
This has led to the loss of 30% of police staff posts and 65% of police community support officers posts, plus most of the capital’s police station front counters and 120 police buildings.
Latest projections show that if the funding crisis does not end, police officer numbers in the capital could fall below 27,500 by 2021 – a dangerous 19-year low.
In Greater Manchester, the police service has faced cuts of £215m since 2010, which has resulted in the loss of 2,000 police officers, a 25% reduction on 2010 levels, and 1,000 police staff.
Labelling the cuts "unsustainable", the Mayors added: "We urge you to use the Budget on November 22 to end the real-term cuts and to put public safety first.
"To put it bluntly, if you continue with real-terms cuts you will be putting at risk the safety of those who live, work and visit our cities without an end to the years of real-term cuts.
“We implore you to use the Budget to ensure the continued safety of the people who live and work in our great cities and the millions of visitors we receive each year.
"We need a real-terms increase in police funding, ensuring that the national and international work that the police in our cities do on behalf of the rest of the country is properly funded.”
The Autumn Budget will be published on Wednesday (November 22).
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