Following an initial trial period Barking and Dagenham, Havering and Redbridge’s police merger is to be made permanent.

Barking and Dagenham was one of five guinea pig boroughs the Met tested mergers out on - but the system is now going to be rolled out across London as part of a cost-cutting initiative.

The pilot had mixed results. In the tri-borough merger the number of police complaints soared once the pilot began.

From November 2016, the month before the merger, to December, the first month of the trial, the number of complaints trebled.

Response times were hit badly by the trial, with the average wait being almost 40 minutes in June.

Mayor of London Sadiq Khan branded the failings “unacceptable” and response times eventually recovered.

Scotland Yard said they have worked to “identify the lessons learnt” to help ensure a smooth London-wide rollout, which is expected to take a year.

The Met needs to deliver £325 million of cuts by 2022, with officer numbers expected to fall to 30,000 by April having been at around 32,000 under former mayor of London Boris Johnson.

London will now be divided into 12 Basic Command Units (BCUs) as opposed to the previous system which separated the force into units along London’s borough boundaries.

Savings will be made by boroughs sharing buildings, resources and staff.

The Met faces a “significant financial challenge, alongside increasing demand,” according to Scotland Yard.

“We need to plan for a future with less and become more resilient so we can continue to meet our financial and operational challenges,” they said.

As well as cutting overall costs, the merger will also free up more money for neighbourhood policing, safeguarding and emergency response.

Deputy assistant commissioner Mark Simmons said: “Local policing is at the heart of what the Met does every day and we will improve it further by offering a service that is more personal and responsive to London’s needs.

“Our new structure will give us the resilience and consistency we need across the whole of London, so we can continue to respond to large scale incidents and meet the financial and operational challenges we are facing.”