Has anyone ever come across a credit card that uses British pounds as a base currency that allows you to rack up air miles for purchases in Britain?

My British husband and I travel to the UK frequently, charging our purchases on his British credit cards that offer NO AIR MILES. We don't want to use an American credit card that has a base currency of dollars, as that would incur high currency exchange fees. We would prefer to use a British credit card that will allow us to earn miles for £ charged.

We've heard that Barclays offers such a card, but can get no information from Barclays or British Airways that confirms this. Both organizations say they've never heard of such a thing!

If anyone can offer help, we'd appreciate it.