A former subpostmaster has spoken of his “joy” after Parliament backed legislation to exonerate those caught up in the Horizon scandal, and his “disgust” at those who did not “stand up and do the right thing” at the time.

Lee Williamson, from Castlederg, Northern Ireland, said the last five months have been “surreal” and that the ITV programme Mr Bates vs The Post Office was “the best gift we could have received”.

The 49-year-old, who ran the Post Office in Portstewart, pleaded guilty to fraud by false representation in 2014 and was sentenced to 18 months in prison suspended for three years.

He has been going through the Court of Appeal process since 2022.

“It’s been a real roller coaster,” Mr Williamson said. “We were looking forward to the July date then obviously news of the Prime Minister calling the General Election, it introduced a bit of chaos into proceedings.”

He said he had a “lot of emotion” after the news on Thursday evening, adding: “It’s been a difficult 12 years, I’m very grateful that it’s through.

“I’m still coming to terms with it.

“My overriding emotion is joy and gratefulness.

“I think that TV programme was the best gift we could have received to move the whole process forward at unimaginable speed.

“This has been going on for a number of years, the public inquiry has been going on for a number of years, the drama brought it into people’s homes.

“You felt very isolated and felt like you were up against one of the most iconic brands in the UK, the programme turned the tide for us.

“The people that have had a negative effect, they will hopefully be held to account.

“I’ve encountered a lot of good people and I try to focus on that.

“It’s a good day in all this.”

Mr Williamson said the three things he wanted to accomplish were the opportunity to go back to court and say he was not guilty, get an appeal and to be exonerated.

He added that he was hoping to take his family on holiday with compensation money.

Mr Williamson took over the Post Office in Portstewart in 2003, then said he started to encounter issues with Horizon about five years later.

He started to notice shortages of £100 and in one instance a shortage of exactly £1,000.

He said: “You try to phone for help, my office was open until 5.30pm and after 5.30pm it was nearly impossible to get through to somebody.

“It was almost parallel to what was on the programme.”

Mr Williamson said he put the Post Office up for sale in 2011 but two sales fell through.

He described the period as a “very dark stage” in his life.

Mr Williamson was suspended on May 22 2012 after being blamed for a shortfall of about £16,000, then resigned later in the year, he said.

In 2014 he pleaded guilty to fraud by false representation and was sentenced to 18 months in prison suspended for three years.

His said he felt “relief” when years later he was told there were others in the same situation and he learned of Fujitsu’s faulty Horizon IT system, adding: “I think the hardest critic is yourself, I’d really beat myself down.”

The father-of-three added: “My overriding feeling is disgust that so many people were involved, not one of them had the conscience to stand up and do the right thing.

“I would’ve thought somebody would’ve said ‘this is wrong’.

“In the inquiry they are just protecting themselves.”

The Horizon scandal, which has been described as the most widespread miscarriage of justice in UK history, saw more than 700 Post Office branch managers handed criminal convictions after faulty Fujitsu accounting software made it appear as though money was missing.

The Post Office (Horizon System) Offences Bill will receive royal assent on the final sitting day of Parliament before it halts its business ahead of the July 4 General Election.

The Bill will quash convictions of theft, fraud, false accounting and other offences for subpostmasters who have suffered as a consequence of the Horizon scandal, and relevant cautions will be deleted from records.

The Bill will apply in England, Wales and Northern Ireland, affecting those who were prosecuted by the Post Office, Crown Prosecution Service (CPS) or Northern Ireland authorities in the years 1996 to 2018.

The Scottish Parliament will pass its own law to a similar effect north of the border, because of Scotland’s distinct legal system.