I'm in second year, and I'm getting solid first marks. You probably could spend most of first and second year socialising if you don't have a job, but I do. Living on £1 a day in London including rent? That's not possible, even with very cheap place to live, £400pm for arguments sake, although that's probably not realistic you're already at nearly £13 a day. Even cheap halls at £99pw are more expensive than that. To live on £1 a day just covering rent with no extra costs, your rent would have to be at a maximum £28 p/m. You certainly can't socialise on that kind of money.
If you meant excluding rent and bills, say they cost £15/day (which is still unrealistically cheap), plus your £1 for living expenses, that's a monthly cost of £480. Per academic year, that costs about £3840. While this is well within the threshold of the maximum student maintenance loan, remember you'll still have to pay travel costs (you can't really stay within walking distance of your house for the entire time you're in London), buy books (which can get very expensive), pay for other materials for coursework. At a minimum. University, and living in London generally is very expensive...
Mostly, I'm just thinking, how do you even eat on £1 a day? That's pretty much one tin of baked beans plus a slice or two of bread per day. Or maybe some rice. Luckily nobody has to pay medical costs here...
Also, I'm interested as to whether or not you think a gap year internship is still really important if I'm already working? I've had two jobs so far, that's quite a lot of experience for someone who's only in second year, and a lot more than many graduates I know...