UK Airport Chaos - Technical opinion

From what's come out in the news today, I present some possible technical reasons as to what could have happened at with the NATS systems on Monday.
I'll follow this up with an run through of the report once it's published.
Thumbnail image: Sean MacEntee from Monaghan, Ireland, CC BY 2.0 creativecommon..., via Wikimedia Commons
Sky news interview with Martin Rolfe: • UK air traffic failure...

[@implodabubble]

This vid was recommended by RUclips. May the algorithm be in your favour and launch you into popularity.

[@jerryorange6983]

Yesterday Gatwick Airport, I went to "British e-gates" to go through the control.
An African guy came in with a portuguese passport, I told him it's not an e-gate for him and he should go to other gates - he told me he don't understand and he speaks "spanish only" , he went through e-gates without any problems.
Great border control.
I hust wonder whether I need a passport at all. I bet I can borrow my wife's one and get through too. :) .

[@PkKingX11]

The e-gates work for UK+EU ePassports. Portugal is in EU.

[@nickf619]

Just doesn’t work other way round, UK can’t (in general) use EU e-gates