Why is £1 taken and then refunded when a user registers in a Payment group?

When a user adds a new card to their Wallet in the Insight system the card has to be authorised before it can be used to take payments. When the card is added to the Wallet and the payment Processor is Protx then you'll see 2 transaction types used:AUTH, CAPTURE, REFUND. A description of these follows:

AUTH - This is necessary in the Authentication of the card, no money is actually taken through this transaction type even though the financial report will display £1 against the AUTH.
CAPTURE - This is required to authenticate a card with the Protx payment processor so we can use the REPEAT payment type. The amount specified e.g.£1 will be a real debit from the card holders account.
REFUND - This is necessary to refund the £1 CAPTURE that was required for authentication. This will automatically happen immediately after the CAPTURE payment. The user shouldn't see these transactions on their card payment statement as any money taken is automatically refunded within the same day, it's possible however in some cases they may be listed on some card statements.