Sub-postmasters are responsible for the everyday management of more than 11,500 post offices across the UK.
In July, former business secretary Sir Vince Cable told the Post Office inquiry that he had wanted to “address the imbalance” between the Post Office and sub-postmasters by creating a “mutual structure”.
He said he had raised some of these issues with the then Post Office boss Paula Vennells, but the change “unfortunately never came to fruition”.
Instead, the Post Office was split from the Royal Mail group under Sir Vince’s watch and remains a government-owned company.
The relationship between the Post Office and the sub-postmasters has received widespread attention following the Horizon scandal.
Between 1999 and 2015, more than 900 sub-postmasters were wrongly prosecuted after the faulty Horizon IT accounting system made it look like money was missing from branch accounts.
It has been called the UK’s most widespread miscarriage of justice.
Hundreds of affected sub-postmasters took legal action against the Post Office in 2019, led by Sir Alan Bates – with some still waiting to be compensated.
An ITV drama about the case in January sparked renewed public interest in the scandal.
The Metropolitan Police said it was investigating the Post Office for possible fraud committed at the time.