Massive changes could come to policing in Wandsworth, Kingston, Richmond and Merton in May, with the four borough forces set to merge.

The areas would come under one Basic Command Unit (BCU) on May 23 if the scheme is approved, with the senior leadership team from all boroughs moving to the new Kingston headquarters.

Mayor of London Sadiq Khan set up pilots of the scheme in Camden and Islington, and Barking and Dagenham, Havering and Redbridge in April 2017.

The plan is for police operations in boroughs across London to be joined into clusters.

He made the decision in a context of heavy cuts to the Metropolitan Police budget by central government, telling the London Assembly in September he was “not going to pretend that one of the motivations around borough mergers and BCUs is not to save money”.

The south west London cluster is the only area with four local authorities merging into one force.

But it is not yet known how much the scheme is expected to save – an evaluation of the pilots is to be released soon, but Mr Khan was unable to give figures to the London Assembly when asked in November.

Deputy leader of Wandsworth Council Jonathan Cook said: “We are urging the Mayor to pause and reconsider these proposals.

“This proposed new management structure will make senior officers more distant, less accountable to the communities they serve and less able to concentrate on important local issues.

“Even at this late stage neither the Mayor nor his deputy are able to say how much cash this move will save. How can Londoners judge whether this is a worthwhile scheme without knowing these important numbers?

“It is not too late for the Mayor to reflect carefully before pressing ahead with this plan to spread local police commanders so thinly on the ground.”

For the scheme to go ahead in May, it will have to be agreed upon by the Mayor’s Office for Policing and Crime – a Metropolitan Police spokeswoman said the decision will be based on lessons learnt by the pilots.

The Deputy Mayor for Policing and Crime, Sophie Linden, said: “No formal decision has been taken around the proposed Borough Command Unit mergers. However, the government’s continued cuts to police budgets since 2010 mean change is needed in order to function with fewer police officers in the future.

“Even with the Mayor’s planned increase to Council Tax, the government settlement represents another real terms cut to resources as costs and pressures continue to rise.

“We are aware of the concerns around these proposals and the pathfinder boroughs are being evaluated as we strive to maintain the safety of Londoners.”