Reports from sub postmasters and mistresses on glitches experienced with their Horizon accounting system continue to crawl out of the woodwork. 

Here are some extracts from a letter sent by a postmistress to Issy Hogg, the lawyer trying to pull a case together on behalf of a number of retailers who claim that the system and not them is responsible for hundreds of thousands of apparently missing pounds.

"We took over this office in 2005 within three months it was £5,000 in the red. Nobody could tell me why. The area manager created a second stock unit account and moved the £5,000 to that account.

"He left us with instructions to just ignore it which we duly did. About two months later he phoned to say 'they' had resolved the problem and closed the second stock unit with no explanation. 'Tis a mystery to this day."

Now here is where the spooky stuff starts: "My office is in an air force base. About three years ago they had an attack simulation. During one fly-past of the so-called enemy my Horizon system went mad and started registering sales of 1st class stamps as the aircraft flew over. Fortunately, at the time we had no customers in the office so were able to delete them, but the question remains: why did that happen?"

When the computer on the second position died a few weeks later, she got chatting with the engineer over the strange simulated sales of stamps. "He explained that the Horizon system is un-screened, therefore could be influenced by outside electromagnetic frequencies radar, laser-guided weapon systems lock-ons, microwaves, high-frequency radio transmissions, solar flares and so on but the PO would never concede that possibility."