There are many well-wishers on Twitter today, sending lots of luck to the sub-postmasters and postmisstresses. They include Reverend Richard Coles who, for all you 1980s pop-pickers out there, was also a member of The Communards.

The Court of Appeal is expected to hand down its judgement shortly.

Horizon was introduced into the Post Office network from 1999. The system, developed by the Japanese company Fujitsu, was used for tasks such as transactions, accounting and stocktaking.

Sub-postmasters complained about bugs in the system after it reported shortfalls, some of which amounted to many thousands of pounds.

Some sub-postmasters attempted to plug the gap with their own money, even remortgaging their homes, in an (often fruitless) attempt to correct an error.

Image source, PA

Between 2000 and 2014, the Post Office prosecuted 736 sub-postmasters and sub-postmistresses - an average of one a week - based on information from a recently installed computer system called Horizon.

Some went to prison following convictions for false accounting and theft, many were financially ruined and have described being shunned by their communities. Some have since died.

After 20 years, campaigners won a legal battle to have their cases reconsidered, after claiming that the computer system was flawed.

Today Programme
BBC Radio 4

Noel Thomas from Anglesey, is one of the postmasters who will learn today if his conviction for stealing from the Post Office will be quashed by the Court of Appeal.

Mr Thomas ran a Post Office in his village and around 2005 discovered a £50,000 discrepancy. "I had been in touch with the Post Office. They kept telling me ‘carry on, we’ll sort it out’."

He said two auditors visited and seemed to accept his explanation.

"But the meantime, two investigative officers turned up. I was accused of theft and the following year, 2006, I was sent to prison."

Mr Thomas has always maintained his innocence but the conviction had a devastating impact on him and his family.

"I really fell off the ladder" he told the BBC's Today programme. "You soon find out who your friends are."

While Mr Thomas said he will fight for compensation from the Post Office, he said: "I don’t want a load of money, all I want is my money back, the money I worked for."

He estimates he lost £250,000 and hopes he will be made whole financially. However, Mr Thomas said: "It has been hard, it has been difficult.

"The last year has been very difficult – we lost our eldest son through cancer. He was 50. It is not easy."

Image source, PA Media/Jo Hamilton/BBC

In all, 42 sub- postmasters and postmistresses will hear today whether the Court of Appeal judges will clear their names. A full list of their names is available on the daily court listings here, external.

Hundreds were prosecuted based on evidence provided by the Post Office and so far, the Criminal Cases Review Commission (CCRC) has referred 51 cases back to the courts.

Six people had their convictions overturned last year.

Kevin Peachey
Personal finance reporter

This is a huge day for 42 former sub-postmasters and postmistresses in the bid to clear their names.

They were alone when investigated and prosecuted by the Post Office – being made to believe each of their cases was unique.

Now, they are a group united by the belief they were convicted – and their lives turned upside down - on the basis of flawed computer system evidence.

But, whatever happens today, this is not the end of the story. Others may follow. Indeed the Post Office is helping to identify other cases.

There is also much more to come on the question of compensation, not least who will ultimately pick up the bill.

A crowd is gathering outside the Royal Courts of Justice in London ahead of the judgement, which is expected to be handed down remotely shortly after 10:30am.

Want to brush up on the Post Office scandal? Read the whole story here.

Welcome to the BBC's live coverage of the ruling at the Court of Appeal when 42 sub-postmasters and postmistresses will learn if their convictions for stealing money will be quashed amid a Post Office IT scandal.

They were convicted - and in some cases sent to prison - for errors made by the Post Office's Horizon computer system which was used in branches.

This day has been a long time coming.

The flawed computer system was first installed in 1999 and postmasters and postmistresses have spent years trying to clear their names.

Stay with us as we bring you all the developments as they happen.