They outsourced them to India, I imagine, along with everything else. This is what you get.
Indeed, they had virtually no IT issues when their IT was in house, based near Heathrow.
Since outsourcing it to more "cost effective" countries, they have had a major hack (for which they are looking at a £180m fine), and now 2 separate systems failing.
As those that work in this sector of the industry, whilst some individuals may be good, on the whole, these outsourcing to low cost countries (ex soviet bloc parts of Europe, India and the far East) will categorically, definitely, guaranteed end up as a complete fuster cluck. But it is cheap... ...until you consider the impacts of each balls up.
Now go and do the needful.