https://www.theregister.co.uk/2019/04/02/why_the_tax_man_needs_4000_it_staff/

OpenInfra Days UK 2019 The British tax man loves the cloud, but anyone who thinks public infrastructure can be run by a skeleton crew should think again: HMRC has no fewer than 4,000 IT staff who deliver around 140 digital services.

... people were really reluctant to do on-call because of the problems we had