This is not just a technical issue; it is a human issue. The attempted reassurance by the Prime Minister just does not wash. In Greater Manchester, some of the missing cases date back to 18 September. That is two and a half weeks ago. There are three very serious consequences: first, it is now much harder to reach the contacts of the 16,000 people after so long; secondly, even if they are contacted successfully, for many the self-isolation period has already expired; and, thirdly, important decisions on local restrictions were made using the wrong data. Some £12 billion has been invested in this system, and yet a basic Excel error brings it down. No wonder it has been described as “intergalactic” incompetence. Why, at this crucial moment, did it take so long to catch this error and address it?