The Met Police fears it could have to cut as many as 2,300 officers due to a funding squeeze, having a “seriously detrimental impact” on the force’s ability to fight crime.
Met Commissioner Sir Mark Rowley is expected to caution on Tuesday that officers will have to be taken off the street due to a £450million funding gap.
The force is preparing for reductions of up to 2,300 officers out of a force of 34,000 and 400 other members of staff may also be cut.
A report by the commissioner explained the Met “will be forced to make tough choices to reduce the service we offer Londoners”.
The report adds that the force has long expected to be in a difficult position for the next financial year.
Sir Mark explained the Met Police has exhausted its reserves with a gap in funding driven partially by “unfunded pay increases”.
The report added that the force “are committed to making ourselves as lean as possible as an organisation” and seeks to find £100m worth of efficiencies.
Key areas of the force are expected to be protected, with Sir Mark promising not to make any cuts to “already overstretched emergency response teams”.
The Met said victims of rape, serious sexual offences and child abuse and exploitation remain part of its “highest priority” and it will protect investment in teams working across public protection.
It has also tried to limit the impact on its frontline work.
But the Commissioner’s Report explained in a worst-case scenario the force will be “scaling back our ability to tackle serious violence and organised crime by cutting the teams that proactively target some of the most harmful offenders”.
The force’s Flying Squad, which helps tackle armed robberies, kidnappings and other serious crimes, will no longer have firearms under the changes.
Meanwhile, the Met’s dogs unit and mounted branch may also be significantly cut back – reducing its ability to respond to police incidents on the roads.
There may also be cuts to teams which help the Met get “ahead of criminals, track down wanted offenders and gather vital evidence”.
The force has announced it may have to move all its intelligence teams into a single command and reduce their size.
Specific teams such as the Royal Parks police, who currently patrol areas such as Richmond Park and Bushy Park, could also be slashed.
The force is understood to have asked the Home Office for extra funding to try and cover its costs and it has been in negotiations to increase its funding for next year.
Last month, Sir Mark warned of “eye-watering cuts to the services we provide to London” as the force is hit by a growing financial crisis.
The capital’s top officer insisted Scotland Yard had run out of ways to plug funding gaps and he was “deeply troubled” by the situation it was facing.
“This is not just about this year’s decisions, but it’s a cumulative effect of decisions over the last decade or so which have put us in a more and more precarious position,” he told BBC Radio 4’s Political Thinking with Nick Robinson.
The scale of the Met crisis was also laid bare earlier this year when the force, which has a budget of up to £3.5 billion to keep London safe and lead the fight against terrorism, admitted it is “not fit to serve Londoners effectively” in its current state.
In evidence to the Police Remuneration Review Body, the Met said a third of its officers will have under four years of service next year as it struggles with pay levels, high workloads and falling application numbers.
The Home Office has been contacted for comment.