The government has offered the Metropolitan police commissioner, Cressida Dick, a two-year extension to her term in office.

The decision was made by the home secretary, Priti Patel, in consultation with the London mayor, Sadiq Khan, and Downing Street.

Those with knowledge of the process say Dick was granted an extension because those most likely to replace her were not yet seen as being suitable for the job.

Dick became commissioner in April 2017 and was the first woman to lead Britain’s biggest police force since it was established in 1829. She had a five-year contract that was due to expire in April 2022.

The decision followed talks between Dick and Patel late last month and it is understood all parties have agreed terms. The extension has to be formally approved by Buckingham Palace as the commissioner of the Met is an appointment by royal warrant.

The extension to Dick’s time as commissioner will be formally announced next week. The only thing that could stop it is a cabinet reshuffle that sees Patel replaced as home secretary and her replacement rip up the deal. This is thought to be unlikely.

Dick’s tenure has been controversial. She angered some with an expansion of stop and search, with community confidence in the Met dropping and the force’s chequered history on race under the microscope.

Others believe she has escaped having to properly account for her role in Operation Midland, the disastrous Met investigation into a VIP paedophile ring that falsely suspected prominent individuals.

Detectives fell for the lies of a fantasist who was later jailed. Dick was also personally criticised by the official report into the Daniel Morgan murder, which accused her of obstructing its work, a finding she denies. She oversaw the fallout after a serving Met officer kidnapped, raped and murdered Sarah Everard in south London this year.

Dick is seen as having struggled to get a grip on violent crime, which she came into office saying was her top priority.

Only John Stevens and Bernard Hogan-Howe have completed their full five-year term as Met commissioner in the 21st century. The commissioners Ian Blair and Sir Paul Stephenson both resigned mid-term amid controversy.

The commissioner of the Met is appointed by the home secretary, who has to have due regard for the views of the mayor of London, Labour’s Khan.