A red rating is the lowest possible security score, meaning that the system is "at a critical level of risk, where the chance of having issues or failures is high, and the potential impact of these issues could be severe." Systems usually get the red-rating because they have old or outdated parts.
For comparison, the next most risky technology belongs to The Department for Work and Pensions which had six red-rated systems. Thirty-four systems across government departments are red-rated.
The figures were revealed to Parliament after a question by Matt Rodda, Labour MP for Reading East and shadow minister for AI and intellectual property, who asked about the number of red-rated systems across Whitehall departments.
According to the Daily Telegraph Rodda said: "The size of this problem is totally unacceptable. The Ministry of Defence, the department mainly responsible for the security of Britain, should not have this many serious failures in its systems. We can't even get the basics right."
His view was backed up by Tory former defence minister Tobias Ellwood and former armed forces minister Mark Francios, both of whom called for an urgent review.
The findings come after a critical report by the Joint Committee on the National Security Strategy with the catchy title A hostage to fortune: ransomware and UK national security, which found that "big chunks of UK critical national infrastructure (CNI) are still open to ransomware, especially in sectors still using legacy IT systems."
It added: "Given the poor use of existing cyber resilience rules, the Government should look into the possibility of setting up a cross-sector watchdog on CNI cyber resilience."
The report, released in December, singled out the Home Office for criticism, saying the former home secretary Suella Braverman had shown "no interest in the topic" presumably because she was too interested in shipping immigrants to Rwanda .
Recent years have seen a steady flow of bad stories about MoD cybersecurity, including the hacking of a supplier by Russian ransomware crooks LockBit, a National Audit Office report saying that old IT systems at the MoD could lead to supply problems for frontline troops, and a fine for a data leak that could have cost the lives of Afghans working with UK forces.
Jake Moore, global cybersecurity expert at security firm ESET said that while updating legacy systems is hard and costly, it's an issue that can't be ignored.
"Costs are often seen as the reason behind a slower fix on such problems. But now it is seen as a serious risk, it should hopefully be seen as vital investments in national security and a key step towards protecting the country's digital infrastructure."