In a submission to the Central London Employment Tribunal, Stephen Clements, 51, claims that two-thirds of the bank's systems were not subject to resiliency tests, leaving "very serious gaps in our ability to recover critical IT systems".

The former head of business continuity at Lloyds alleges that the problems were so severe that they would have cost £200 million to repair.

When he raised the issue with senior management, Clements says he was told the 'burn the paper' on his report and "never bring it out again". He alleges a deliberate cover up to bury the problem due to the reputational risk attached to the issue and the high cost of repairing the flaws.

Clements quit his post in July, just four months after raising the alarm, after he was threatened with a transfer to another post because of his age.

The bank has denied the allegations.