Thousands of UK police officers face losing their jobs by the end of the decade as part of George Osborne’s plans to shrink the size of the state, according to a Labour analysis of figures compiled by the House of Commons library.

Amid warnings of a return to the emergency-based policing of the 1980s, the analysis suggests that the Metropolitan police, Britain’s largest force, may have to cut between 1,300 and 5,200 police officers – out of a total of 31,000 – if the full planned cuts are introduced.

The Commons library made the assessment after it was commissioned by Gareth Thomas, shadow London minister, to assess the impact of a recent warning by the Met commissioner, Sir Bernard Hogan-Howe, that he has to cut his budget by £1.4bn over the current decade.

In a Guardian article last week, Hogan-Howe wrote: “By 2020 the Met will need to have made £1.4bn of savings over a decade – about a third of our budget. We have saved hundreds of millions already, but from 2016 it will become a much harder task.”

Earlier this month, the Guardian reported that the Met needed to find an extra £800m of cuts in the next budget period, from 2016-2020. The Met, which recently announced that it has sold its New Scotland Yard HQ for £370m, believes it can save £400m. But it has yet to identify how it would cut an extra £400m over that period. Other smaller forces around the country face similar cost pressures.

Thomas asked the Commons library to assess the impact on police numbers if the Met sought to achieve the £400m cuts by reducing the force’s headcount. The library calculated that the average cost of a police officer in London is £77,000 – roughly 20% higher than the average of £63,900 in England and Wales.

On Labour’s analysis, if the Met had to cut its budget by £100m in 2016-7, it would have to trim police numbers by 1,298 if it relied on officer headcount reductions alone to achieve that level of saving. If the same level of saving was required for each of the four years, 5,194 posts could be at risk.

Thomas said: “George Osborne’s plans for cuts in Metropolitan police funding ... would have a devastating impact on the quality of policing in London and be the final death knell for high visibility, bobby-on-the-beat local policing.”

The Home Office dismissed the Labour claims, saying the Met would not have to rely on headcount reductions alone. A source said: “Police spending cuts do not mean simple salami slicing of police officer numbers. And police officer numbers are not the test of how to cut crime – what matters is how they’re deployed, not how many are employed. The experience in this parliament – in which we’ve cut spending by 20% and crime has fallen by more than a fifth – shows that it’s possible to do more with less.”

Thomas added that the cuts would herald a return to the policing of the 1980s which focused mainly on responding to emergencies. He said: “There is now a real fear that what the coalition government are planning is a return to 1980s-style policing, with people responding to emergencies only rather than proactive community policing which, until recently, people have come to expect.

“This gives the police better access to intelligence about what is going on in the community, about where potential criminal activity may take place and the police are able to be much more pro-active about getting access to that sort of intelligence. If there are fewer police, they will have to rely on people phoning as a result of an emergency rather than getting access to that intelligence. This might have sounded like a good idea to George Osborne and the small circle he moves but this is not the standard of policing people have come to expect and want.”

Hogan-Howe issued a stark warning in his Guardian article that public safety could be put at risk if the police and its partners – local authorities, other emergency services and the criminal justice system – fail to cooperate as cuts were introduced.

“Our partners face their own cost pressures, and the big concern is that if we don’t work together, with a shared view of the risks, public safety will suffer,” he wrote. The Met commissioner suggested that savings could be made by shrinking the 43 police forces in England and Wales to just nine and for the pooling of 999 calls for the three emergency services.

Downing Street dismissed Hogan-Howe’s call for a reduction in the number of police forces, prompting fears that cuts will have to be introduced in other ways.

Labour believes reducing police numbers would be a dangerous process. Under the A19 procedures, which are designed to protect their independence, police officers can only be removed for disciplinary reasons. The only way to do it is to require officers with at least three decades of experience to retire. This means that officers with experience would have to be targeted.

Jack Dromey, the shadow policing minister, said: “The first duty of any government is the safety and security of its citizens. But from Lincolnshire to London, the message is clear. The immense cuts to our police service is undermining neighbourhood policing and putting at risk public safety and the protection of the vulnerable.”

The Commons library is impartial and does not endorse individual party policies. It carries out research on behalf of MPs, including frontbenchers. Labour asked the library to assess the impact of achieving £400m of spending cuts in the Met solely through a reduction in police numbers. The library, therefore, did not assess other areas of police spending that could be cut.

Sir Hugh Orde, the president of the Association of Chief Police Officers, told the Guardian: “Policing has lost 34,000 officers and staff since 2010. Until now the focus has largely been on back and middle functions. However, with every round of cuts the challenge grows more acute.

“The last royal commission, of 1962, took place at a time before colour television, the internet or mobile phones. We have said consistently that only a fundamental review of force structure will enable us to make the savings demanded by austerity whilst remaining effective in the 21st-century landscape. This is what we must do.”

Mike Penning, the policing minister, said: “There is no question police will still have the resources to do their important work. Her Majesty’s Inspectorate of Constabulary recently found that forces can successfully manage to balance their books while protecting the frontline and delivering reductions in crime. We have made it easier for the police to do their job by cutting red tape, scrapping unnecessary targets, and giving them the discretion to use their professional judgment.”