The British government on Friday announced a new head for the country's biggest police force, ordering him to rebuild public trust after a spate of scandals.

Home Secretary Priti Patel said Mark Rowley had been appointed as the next commissioner of London's Metropolitan Police.

Patel called Rowley, a former head of the Met's counter-terrorism unit, a "distinguished and exceptionally experienced police officer".

But she said the commissioner's job was "one of the most important and demanding jobs in policing", particularly giving the force's recent "failings".

"Rebuilding public trust and delivering on crime reduction must be his priority," she said in a statement.

Rowley, 57, said he was "deeply honoured" by the appointment, which puts him in charge of more than 43,000 police officers and staff, and a budget of ?3.24 billion ($3.9 billion).

The Met polices a population of more than eight million people over 620 square miles (1,605 square kilometres) of Greater London.

Scotland Yard, as the force is also known, was last month placed in special supervision by a police watchdog body for failing to hit standards targets.

Mark Rowley, who headed the response to the 2017 London terror attacks, has been appointed the new head of the Metropolitan Police
Mark Rowley, who headed the response to the 2017 London terror attacks, has been appointed the new head of the Metropolitan Police AFP / NIKLAS HALLE'N

Former commissioner Cressida Dick stood down in February having lost the backing of London mayor Sadiq Khan after months of pressure over the conduct of her officers.

Chief among them was the jailing of a diplomatic protection squad member for the high-profile kidnap, rape and murder of a young woman -- and the heavy-handed policing of a vigil for her.

Other officers have been convicted of taking unauthorised photographs of murder victims at crime sites, as well as the sharing of racist and abusive messages on social media and messaging apps.

Rowley promised to "lead the renewal of policing by consent which has been so heavily dented in recent years as trust and confidence have fallen".

He vowed to be "ruthless in removing those who are corrupting our integrity".

The officer has more than 30 years' experience and previously served as chief constable of Surrey Police in southeast England.

He joined the Met in 2011 and led its response to terror attacks in 2017, when a van smashed into pedestrians on London Bridge before three assailants went on a stabbing spree.

Eight people were killed and about 50 were hurt in the attack, which was claimed by the Islamic State group.