As reported in yesterday’s story, which was broken by Computer Weekly, the two companies were in the process of negotiating a new contract to run from October 2024.

However, a cyber attack on MoneyGram which interrupted operations for several days, led the Post Office to offer shortened contract terms which were rejected by MoneyGram

MoneyGram subsequently contacted postmasters to express its disappointment at the Post Office decision and how it chose to portray the cyber security incident to its customers.

"We are shocked and disappointed by the message you received from the Post Office, which was both misleading and a breach of the current agreement’s confidentiality," stated the letter which was also shared with Finextra.

"We have always held our relationship with you in high regard as we deliver value for our shared customers. MoneyGram believes it had a binding agreement on a new 12-month extension with the Post Office. However, the Post Office leveraged our unforeseen cyber incident to materially alter the duration and terms of the agreement in a way that was detrimental to MoneyGram.

"Our cybersecurity experts have determined that the incident has no effect on any of our agents’ systems. We are pleased to report that we have resumed operations in every country outside of the UK and are working diligently to resume operations here.

"It is unfortunate the Post Office has taken this stance after our trusting partnership of over 25 years. We sincerely hope that we further the dialogue with the Post Office and can continue to work with you in the future," concluded the letter.

It is not the first time that the UK Post Office has attracted controversy over its relationship with third parties and technology. It had a long-running dispute with sub-postmasters over its Horizon accounting system supplied by Fujitsu.

The affair has been called the biggest miscarriage of justice in British corporate history.