How to choose unis in UCAS application for CS undergraduate course?

My son is currently studying Maths, Further Maths, Computer Science and Chemistry in Yr12. His current working grades in these subjects are A*A*A*B, respectively. He is interested in studying CS (with ML and AI) at Imperial London or University of Cambridge or UCL or KCL or Southampton University.
Are these too ambitious preferences? Any advise on choosing unis and computing courses based on these 4 A-levels and working grades? Is application with physics A-level prioritised over chemistry one for Computing courses?

First I want to say a big well done to your son, his working grade in year 12, the year that most mess about, is 3 A*s and a B?!?? Your son is amazing. So congrats to him.
That's good that he's going for those unis, it's not too ambitious, he's evidently doing well and if he keeps it up then by the time of his final exams he'll have probably upgraded his grades a little more. Imperial, Cambridge, UCL? Those are top unis and if I think he can do it, I don't even know your son but I'm already proud of him haha
Chemistry is definitely not a priority as such, yes, he should work on it to improve his grade because why wouldn't you, but for studying CS his other subjects are the correct ones, and the ones Unis will focus more on. If he gets A*s in FM, Maths and CS then, with a good personal statement, he'll get into those unis easily.
He's doing Chemistry too and I'm sure he'll improve on that if he wants to, but chemistry is not needed at all for Computing courses. The 3 A-Levels Universities recommend students to do for those a CS degree is exactly the 3 he's doing and getting all A*s in.
All the best to your son💪

This is quite a poor judgement. Being a computer science applicant myself, I can say that the admissions in the last 2 years have been very ruthless. CS is extremely oversubscribed and there are 4A star candidates being rejected left and right. A simple reddit search will show you that Bath, Warwick, Kings and Durham (not even mentioning UCL, Oxbridge, Imperial) have all been rejecting large amounts of such candidates. The number of applicants to UCL has doubled since 2020-2021. You have to have very good extracurriculars, do amazing in the admission tests if going to Oxbrimp. Other unis dont offer admission tests, so at this point the admissions are almost like a lottery. How do you differentiate between candidates when 50% of them have got the top grades?
If he truly is passionate, I would advise to consider safeties very carefully. Over the summer, try and create projects. Also, maths is very very important. Ideally, a big part of the personal statement should be on maths.
If I was applying again, I would probably apply to a maths course, and later on choose modules which are tied to computer science. Self teach the things that Id be missing out.
It's up to you. But again, be very careful. Some people got no offers at all, even though they had top grades. And not just a bit, lots of them. Google freedom of information requests to see admission statistics. Use them to your advantage.
Best of luck

I'm not gonna say you're wrong cus that'd be absolutely stupid of me because you'd know more about the degree you are applying to and I'm not, however, I'd like to say that I did say he needs a good personal statement for CS, which means has done a lot of extracurriculars and with that evidence his PS proving his capabilities.
Furthermore, I know many students from last year who applied for CS and 4/7 of them got in, my school is trash, and I won't deny that they did a lot to get in, if I remember correctly their grades roughly averaged from AAAB to A*A*AA
It's hard but if they can do it then so can this kid. Obviously look for other options because I know CS is hard to get into.
Nobody who's really passionate about a subject/degree will not study hard or tell themselves they can't do it, everyone has moments of self-doubt yes, but the one thing that separates truly passionate people to the average person is that they will work so hard, they will push themselves and they will do their utmost to get to where they want to be. I'm not one of those people, but I've met them, and they are just absolutely inspiring and amazing people who half the time don't realise it themselves

2 A stars 2A is probably the lowest you can apply with. For ucl and anything above that would be too low. Now, this is not about “doing” and “making it happen”. It is literally luck.

Computer science is really competitive, especially in the last two years, but as a CS applicant this year, your son’s well equipped for the best universities. One thing to consider is that since the best universities are rejecting large numbers of people (and I know from experience) you should consider making your personal statement as centred around maths and computer science as possible (probably the only reason I got a place at Southampton). Generally though, he’s in a really good position. Best of luck!

Computer science is really competitive, especially in the last two years, but as a CS applicant this year, your son’s well equipped for the best universities. One thing to consider is that since the best universities are rejecting large numbers of people (and I know from experience) you should consider making your personal statement as centred around maths and computer science as possible (probably the only reason I got a place at Southampton). Generally though, he’s in a really good position. Best of luck!

Are you doing CS at the university now? How is it?

Not yet, currently working towards meeting my offer. Exams start soon so I’m revising a lot. Looking forward to uni though since I’ll be learning a lot of new stuff, as I don’t do CS A-level

What's your offer? Is it A*AA as well?