Paula Vennells, the former chief executive of Britain’s Post Office, said on Tuesday she would hand back a national honour after mounting public anger over the wrongful conviction of postal staff on her watch.

The more than 20-year scandal, one of the biggest miscarriages of justice in British history, has received renewed attention since a TV drama showing how it disrupted the lives of hundreds of sub-postmasters aired last week.

More than 1.2 million people have signed a petition demanding that Vennells’ CBE honour, which ranks just below a knighthood or damehood and was awarded to her in 2019 for services to the Post Office and to charity, be rescinded.

Vennells said in a statement she was focused on co-operating with an ongoing public inquiry into the scandal and that she had maintained her silence so far because she believed it inappropriate to comment before giving evidence to the inquiry.

“I am, however, aware of the calls from Sub-Postmasters and others to return my CBE. I have listened and I confirm that I return my CBE with immediate effect.”

The scandal saw staff at the state-owned Post Office wrongly prosecuted or convicted between 1999 and 2015 for false accounting, theft and fraud, because of a glitchy software system that incorrectly showed money missing from accounts.

Prime Minister Rishi Sunak’s government has also faced pressure to ensure all victims of the scandal receive adequate compensation and see their convictions overturned.

The government said on Tuesday it was urgently working on plans to clear the names of postmasters and that it would announced the details shortly.

Asked if the government would take the exceptional step of legislating to quash the convictions, Justice Secretary Alex Chalk told parliament: “These were truly exceptional circumstances … It is truly exceptional, it is truly unprecedented and it will need an appropriate resolution.”