no
No. As it stands , you'll need to pay around £50+ for a private PCR test ( not a free NHS test)in the UK before you depart . Then get a test ( possibly a lateral flow (paid for) whilst you're in Portugal before you return to the UK. Assuming all these are negative and you've been filling in your locater form for the stay, you're good to go.
This could possibly change in a few days , if Portugal relax certain rules, but they may not, which is understandable . I think the test in Portugal is the elephant the room at the moment . Thousands of English fans queuing up at a private clinic for a lateral flow test to present on entry at the UK border.
If fans are only staying one night, which is understandable , I'm not sure how these measures could be introduced. Hopefully a bit of common sense and practicality can be worked out without putting anyone's health at risk