At the beginning of the pandemic at least 1,356 different corona origin infections came into the UK, mainly from Spain and France.
On each of those occasions somebody brought the infection into the UK from abroad and the virus began to spread as a result.
https://www.bbc.co.uk/news/health-52993734
The failure to ground flights or quarantine people on those flights that were allowed, meant that the virus spread rapidly.
Only now, 10 weeks and 41,000 UK deaths later, are we making an half-hearted attempt at quarantining.
So much for taking back control of our borders. There should be an i quiring about how this error occurred.