Those of us who watched the recent ITV drama Mr Bates vs The Post Office, which portrayed the plight of sub-postmasters caught up in the Horizon scandal in a realistic and powerful way, will have been shocked that such a devastating injustice could happen.

For more than 15 years, the Post Office wrongly prosecuted over 900 sub-postmasters for crimes, including theft and fraud, after faulty accounting software, known as Horizon, showed shortfalls in their branches. This miscarriage of justice has had an enormous impact on the sub-postmasters involved, with many given criminal convictions, and in some cases prison sentences whilst others committed suicide.

It is clear that at the heart of this scandal was a culture which failed to listen to victims and to whistleblowers who tried to highlight the faulty Horizon IT, opting instead to cover up and falsely accuse innocent sub-postmasters. Alan Bates, who led the group fighting to clear their names, described them as ‘little people’ who were ‘fighting a war against an enemy owned by the British government’. That enemy was the Post Office, a trusted and respected organisation, and the postmasters were decent and honest people whose lives and standing in communities were ruined by the scandal.

I was pleased to see the Prime Minister, Rishi Sunak, announce earlier this month that the Government is to bring forward landmark legislation which will exonerate wrongly convicted sub-postmasters caught up in the Horizon scandal. This unprecedented move by the Government will no doubt bring sub-postmasters a step closer to gaining justice and I look forward to supporting it in the coming weeks.

One of the most shocking aspects of the Horizon scandal is the cover up culture which put the preservation of corporate reputation before people and victims. It was a whistleblower who worked for Fujitsu, the company which created the Horizon software, who provided key evidence revealing Post Office accounts could be changed remotely and without the sub-postmaster’s knowledge.

I have raised the importance of whistleblowers in Parliament on numerous occasions, highlighting their pivotal role in shining a light on secrets and cover ups at the heart of this scandal and many others.

As Chair of the All-Party Parliamentary Group on Whistleblowing in Parliament, I have previously brought forward a Private Members' Bill to create an "Office for the Whistleblower". Such an Office would provide protection for every person who is, has been or is perceived to be a whistleblower and safeguard people who speak out against wrongdoing, no matter how powerful the organisation is.