In the face of mounting pressure over the Horizon scandal, former Post Office boss Paula Vennells has announced that she will hand back her CBE.

More than 1.2 million people had signed a petition demanding the honour should be stripped from the former businesswoman and priest as politicians also weighed in.

She told the PA news agency in a statement that she had “listened” to the calls from critics including hounded supostmasters and will “return my CBE with immediate effect”.

But the process is a little bit more tricky than that, and even involves the King. Here is a look at how Ms Vennells will officially lose those three letters after her name.

– How did she get her gong in the first place?

MPs and victims of the scandal have for years called for Ms Vennells to be stripped of the rank of Commander of the Most Excellent Order of the British Empire which she was made in 2019.

Her inclusion on the New Year’s Honours list came despite legal action being launched against the Post Office by 555 subpostmasters back in 2017.

The Post Office said she was recognised for her work on “diversity and inclusion” as well as her “commitment to the social purpose at the heart of the business and her dedication in putting the customer first”.

In a statement at the time, she said she was “delighted” to receive the honour, saying it was “recognition of the hard work and commitment of so many colleagues across the organisation”.

– So why hand it back?

The Horizon scandal that saw hundreds of subpostmasters wrongfully convicted of crimes including theft and false accounting was not just about dodgy IT software but how the Post Office relentlessly pursued workers.

Former postal affairs minister between 2010 and 2012, and now Lib Dem leader, Sir Ed Davey has alleged that there was a “conspiracy of lies” unleashed by senior Post Office managers.

Public fury over the scandal has been intensified thanks to the ITV drama Mr Bates Vs The Post Office.

Prime Minister Rishi Sunak made clear through his official spokesman that he would “strongly support” a review of whether she should hold onto the honour.

Ms Vennells pledged to voluntarily renounce the rank as she said she was “truly sorry for the devastation caused” to subpostmasters and their families.

– How does it all work?

The only person who can actually forfeit an honour is Charles. The King takes advice from the Forfeiture Committee chaired by senior civil servant Sir Chris Wormald.

Typically, the group might recommend someone is stripped of their gong if they are convicted of a criminal offence, or any other behaviour that brings the honours system into disrepute.

But individuals can also signal they want to renounce their honour, as Ms Vennells has now done.

Until the King acts on the advice of the committee, however, Ms Vennells continues to hold the title.

Prime Minister Rishi Sunak’s official spokesman said that those surrendering their honour have to take steps such as “returning their insignia to Buckingham Palace and not making reference to their honour”.

Forfeiture approvals are usually placed in the London Gazette, the official public record.

– Who else is on the ignominious list of former honourees?

Fred Goodwin, the former Royal Bank of Scotland chief executive, was stripped of his knighthood for his role in the financial crisis of 2008/09.

Last year, Dario Gradi, the former Crewe Alexandra manager, was stripped of his MBE over allegations he failed to act on rumours of child sexual abuse.

Raymond Parry, who had been described as a “hero” of the 7/7 London bombings, lost his MBE after he groomed and sexually assaulted a child.

The committee would have considered stripping Jimmy Savile of his knighthood and former Liberal Party politician Cyril Smith his MBE, both over multiple allegations of sexual abuse.

But the Gazette noted that honours cannot be removed from people who have died, because they are “living orders” that individuals cease to be a member of when deceased.