Capital One is a large US bank offering credit cards in the UK.
Its most popular card is designed for use by people with poor credit history, or those who are trying to build up their history for the first time.
The advertised APR on this card is fairly high, but that's a reflection of the perceived risks of lending to those who don't have pristine credit scores. If you can, you'd be wise to always pay off this card in full to avoid interest accumulating.
It only offers one other card, which is a balance transfer card. It comes with no transfer fee and a fairly low APR. If you're not able to get hold of 0% balance transfer cards and have some debts you need to consolidate, it might work well for you.