Only £200m is impressively low for this type of failure. Canada's federal government is on track to waste more than 2.2 billion dollars on a pay system that does not work and needs to be replaced with another billion dollar system ASAP.
In Czechia we have a system where all sellers have to log bills to prevent tax evasion. IBM also provided the system. It cost ~ 15m$ to set up and ~15m$/y to run.
Given the rate of ~millions of bills submitted per day, of which the government only gets the total price and taxes, you have like ~hundred bills per second.
I could scale a gunicorn+sqlite on my 2014 MacBook Pro to be able to receive this rate of requests with a payload which could fit inside a single TCP packet. Sure, there is auth/backups/analytics... etc. Yet, I still just do not see how could IBM charge the extra 14m$ to set that up...
I’m not saying IBM is not still charging the government 14x more than necessary, but at least some of the expense is likely their own fault for having ridiculous requirements.
I don't know how it worked out in terms of budget, but the company ended up in a dispute over billions of euros in damages, mostly from lost revenue.
German Wikipedia source: https://de.wikipedia.org/wiki/Vergabeverfahren_zur_Lkw-Maut_...