Originally Posted by
navatwal
Im based in UK and all my flights originate from the UK
Forgive me, do you want an account with a US bank/issuer? Or do you just want a USD billing card?
If you want a points earning USD card, you could get the Amex ICC (international charge card), it is administered by Amex (UK) and is available in USD - it would earn you Amex Membership Reward points, which you could convert to Avios.
Plenty of UK banks will be able to give you USD billing cards (i.e. billed in the USD currency), easpecially as you move further up the premium banking levels.