He's saying theres a Nepal mutation of the Indian variant detected in Portugal and they're taking the safety first approach by putting them back on Amber. That's my take on the situation. It's all about protecting the UK.
Portugal is saying they can't understand the logic.

The UK Government rhetoric has consistently been don't travel. Yes it's disappointing about Portugal today but just because you're vaccinated doesn't mean you're immune or can't spread it about. Either at your destination or when you come back. I think we just need to accept that any form of summer holiday will require multiple PCR tests and at least 5 days of home quarantine on return which will need to be built into any holiday budget and annual leave that we take.