Just had this from pokerstars today:
"We are writing to you today to let you know about a change in the way that some UK banks are handling gaming transactions. We want to make sure our players understand the changes, so they can make their deposit choices
properly.
Gaming transactions, which have until now been treated in the same way as any other purchase, will be treated as cash advances by the following credit card issuers:
Already in place: MBNA, Halifax, Egg
From 1st May: Mint, Royal Bank of Scotland, NatWest
This means that anyone using their credit card to make a deposit on PokerStars will most likely be charged a higher rate of interest and, in some cases, a handling fee (usually around 2%). We advise you check the terms and conditions of your card carefully, and to contact your bank if you have any questions. (I wouldn't bother as they will be none the wiser

)
Unfortunately, this change is outside of PokerStars' control, as this charge is levied by the credit card company. Please note that we are not making this surcharge, and we do not receive any of the additional charges.
We recommend that where possible you switch to the use of a debit card, as these are not subject to interest charges. We accept Solo, Switch, and Maestro debit cards."
I have been expecting this and no doubt this will happen with other banks shortly and to other sites. I have tried to get my head round this in terms of any real justification for the change, but struggling.