Secret emails have been given to the Post Office by its lawyers. This could help explain why subpostmasters were incorrectly charged with fraud, theft, and false accounting. However, it was a computer error that caused financial irregularities.
A public inquiry has been launched to determine what really happened. 59 of those convicted have now had their sentences overturned.
Insiders estimate that the inquiry will be given tens of millions of documents, spanning over 20 years of e-mails and letters between Post Office staff and internal legal advisers, barristers and solicitors’ firms.

Postmasters charged with theft of Post Office merchandise celebrate outside High Court In London, after being acquitted
The documents will allow the inquiry to test claims made by the Post Office’s former chief executive, Paula Vennells, a part-time priest, that she was led astray by her legal advisers.
The Post Office does not legally have to hand over the papers but volunteered them at the request of the inquiry’s chairman, Sir Wyn Williams.
Without considering legal counsel given by senior management, postmasters claimed that it was difficult to find out how many were being targeted.
Legal sources stated that the inquiry wouldn’t have the legal authority to require the Post Office hand the documents over if the Post Office had not given them up.

Janet Skinner, a former Post Office employee (centre), hugs her family after she was convicted in relation to the Horizon IT scam.
Sir Wyn said: ‘There is now a great deal of work to be done in organising and obtaining disclosure of relevant documents statement here.’
A Post Office spokeswoman said: ‘Following the request by the inquiry chairman, the Post Office has agreed to waive relevant legal privilege for the purpose of the Inquiry to over 20 years of documentation, reflecting our desire to assist the Inquiry in obtaining the information necessary to complete their investigations.
‘While the Inquiries Act does not compel this step, and legal privilege is an important feature of our justice system, this is the right thing to do for all those affected by the Horizon IT scandal.’
It has declined to waive privilege in respect of the postmasters’ compensation scheme, the Historical Shortfall Scheme.