You do know that this approval of the vaccine in 12-15 year olds is just going to move restrictions further down the line until they are all vaccinated don't you?
The vast majority of the British public have June 21st as "freedom day" (the media love a buzz phrase) so will more than likely tell the government to stick it anyways.
Why would we get hit with more restrictions compared to last year when we didn't have a vaccine then?
Erm nope, as protection increases, the end of all restrictions (for good) comes nearer, not further.
A lot of the spread is coming from that age group (along with other unvaccinated age groups), the sooner some of them are vaccinated the faster we will be on top of it and can then "relax". If that gets us to herd immunity faster then this massively reduces our chances of ever needing further restrictive measures, or needing to maintain current ones for as long. It's a bonus, which is great.
Good luck with that, that's if they do decide to hold for a couple of weeks. I actually don't think they will delay (as they won't want the bad press, and morons kicking off), and they may pay the price with a possible third wave, albeit it will likely be lower than the other two waves. Cases are doubling every 14 days at the minute, so even if we did make an error and not delay 21st, then it won't be as bad as March 20, when it was doubling every 3 days.
Also, people have "freedom" now, you should be thankful for what we have. You will probably find that most will accept another couple of weeks as we are, as what we have now is fine over summer, and two weeks now is better than two months in September or whatever.
Last summer we didn't have alpha (which is miles worse) and we also didn't have delta, which is much worse again. The previous coverage of a single vaccine against old variants is less than against new variants, but largely unchanged on a double dose. That's why there's a drive for double doses, and it's a close race between the double dosed and delta. Personally, having just had one vaccine, if we get over 10k cases I won't bother going out, like I have been doing, it;s not worth the risk of long covid, and whatever that ends up as.
I don't think we will need to go "full lockdown" again mind, as vaccines and science will bail us out (like it's bailing us out now), but we could end up with the same restrictions as we have now, in the future, if we go softer too early.