Tesco (I know, I know...) have an own brand IPA made in Scotland - by Harviestoun, I think - that's labelled as a double IPA. It's on special at the moment at £1 for a 330ml bottle. I bought a couple of bottles last night, got it home & saw it's 9.2%!!!
It's one of the hoppiest beers I've ever tasted. I know there's a scale for hops, but this must be near the top of the scale. It's definitely not a quaffing beer, but worth a try, if that's your bag.
They also do a porter, also brewed in Scotland. "Only" 6% ABV! Not as nice as Sainsbury's own brand, as it lacks a sweetness I expect in a porter.