Large cuts to police and other services will endanger public safety unless the next government pushes through radical structural reforms to cut back-office costs, Britain’s most senior police officer has warned.

Scotland Yard commissioner Sir Bernard Hogan-Howe, writing in the Guardian, gives his sternest warning yet about the potential effects of forthcoming cuts, with police preparing to be told this week of even more to come.

The Metropolitan police commissioner says he expects further reductions in budgets whoever wins the 2015 general election. He argues for reforms including mergers of individual forces, which would rip up the historical landscape of policing, to lessen the potential damage.

“There’s a bigger risk to public safety if we don’t take radical action,” Hogan-Howe writes, adding: “We’ve saved hundreds of millions already, but from 2016 onwards it will be much harder.”

In a move that clashes with Conservative party policy, he calls for the culling of more than 30 forces in England and Wales, to create nine super-forces, based on the regional boundaries.

He warns that criminals are moving from the “shotgun” robberies of the past to more sophisticated offences involving data and cybercrime, and says that police need to catch up.

Hogan-Howe’s intervention comes amid real concern among the leadership of the Yard and London government about the level of cuts proposed, which could result in the capital losing in total one-third of its budget.

Police chiefs across the country fear the scale of the cuts to come could decimate neighbourhood policing, vital to preventing crime. Privately they fear a potential return to “1980s”-style policing, of responding to emergencies and little else.

The commissioner’s intervention comes at the start of a dramatic week for policing. On Monday the home secretary, Theresa May, will go before MPs on the home affairs committee, where she will be questioned after the chief of Lincolnshire police last week warned cuts could send his force to the wall.

On Wednesday the Home Office will tell forces about more cuts, with police fearing they will eventually be bigger than the 23% suffered since 2010.

In his article, Hogan-Howe says that others involved in keeping the public safe are also facing large cuts. He writes: “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 sets out an argument for reforms, and cites the example of domestic abuse to show how many agencies can be involved in a case: “Society’s ability to reduce abuse is much more than a policing issue. It’s about a range of agencies – from social services to mental health – having the capacity to intervene early. If we retrench in isolation, the risks to public safety can only increase.”

Hogan-Howe warns that cuts to other public services jeopardise assets the police rely on. He says that police could lose crime-fighting CCTV cameras, which are funded by councils, because local authorities themselves face tough spending cuts: “As they face more cuts there’s an active discussion about whether they can afford to keep CCTV going.” The commissioner adds: “We have to have a shared view of the risks to public safety, from countering terrorism to child protection. We need to be transparent about these risks with the public, politicians and the media, so we can together make informed choices about our priorities.”

Police officer numbers in the capital have been kept so far at 32,000, but with new spending cuts to come it is feared these levels may drop.

Hogan-Howe says: “By 2020, the Met police will need to have made some £1.4bn of savings over a decade – about a third of our budget. We’ve saved hundreds of millions already, but from 2016 onwards it will be much harder.”

Of the £800m of new cuts, the most optimistic private assessment is that the Met can save £400m, leaving it looking for another £400m to save by 2020.

The Met’s Scotland Yard headquarters have been sold, and little-used but costly police counters closed, to deal with the first rounds of cuts. But in his autumn statement the chancellor, George Osborne, made clear to police chiefs they would have to find even more savings.

Hence Hogan-Howe sets out a blueprint for reforms, the centrepiece of which is merging the 43 forces in England and Wales. He argues that they would still remain answerable to their local communities and cites Scotland’s experience of merging eight forces into one super-force.

He writes: “In Scotland, they have survived such a radical transition,” adding that reforms have been introduced successfully in the Netherlands, as well.

The commissioner says it will take “courage” but the benefits would include savings and a faster move to digital policing: “Fewer forces would help us make the vital transition to digital policing. Cybercrime is making the whole notion of jurisdiction less and less meaningful. In the cashless society of 2020, data is the new currency and electronic fraudsters replace the stocking and shotgun robbers of the past.”

Labour are considering the merger of forces, which some believe could produce savings of around 10%. But the Conservatives oppose mergers. Tory insiders say one reason is because MPs from rural constituencies feel their areas would lose out to urban ones, where there is more demand.

But, at the same time, mergers would incur an initial cost, and in a speech in September the home secretary set out her opposition, saying forces could achieve similar savings through collaboration.

Another of Hogan-Howe’s bosses, the Conservative Stephen Greenhalgh, who is London’s deputy mayor for policing, also dismissed the idea in a thinktank pamphlet in April 2014. However, police chiefs have long been in favour of reducing the number of forces.

Hogan-Howe says that money can be further saved by greater private sector involvement, and the merging of control rooms answering emergency calls for the police, fire and ambulance services in London. The commissioner would have been mindful that warnings from other police chiefs about cuts endangering the public have been dismissed by the government as “shroud waving”.