The criminal investigation into the Post Office scandal will be expanded to include 80 detectives from forces across the country.
Detectives will look at potential offences including perjury and perverting the course of justice.
London’s Metropolitan Police first started investigating the scandal in January 2020, but the operation will now be expanded to forces across the UK.
Stephen Clayman, the Met Commander who is overseeing the investigation, said officers understood the “widespread and devastating impact” of the scandal.
“A team of detectives has been painstakingly working through millions of documents manually and with the help of specialist software, in parallel with the public inquiry,” he said.
“This is very time consuming and we cannot cut corners and risk missing evidence.”
He added: “Given the significant scale of the investigation, it has been agreed by the National Police Chiefs’ Council that the next phase of the investigation will be a national policing effort, coordinated by the Met, with the pursuit of justice at its heart.
“We do not underestimate the seriousness of the task at hand and we are determined to carry out a full investigation with independence, precision and integrity.”
Officers have asked the government for £6.75m to fund their expanded investigation, according to The Guardian, which first reported the news.
Hundreds of sub-postmasters were wrongly convicted of theft and false accounting because of the Post Office’s faulty IT system called Horizon.
Fujitsu, which developed the software and the Post Office have been under police investigation for more than four years.
There is also an ongoing public inquiry into scandal, which last week heard testimony from former Post Office chief executive Paula Vennells.
Ms Vennells broke down into tears on multiple occasions during her three days of evidence.
She repeatedly denied any wrongdoing, insisting that she loved the company and had “worked to the best of my ability” during her time at the organnisation
But she was booed by the public gallery and accused by baristers representing victims of the scandal of talking “absolute rubbish”.