WorldPay, an online payment service owned by the Royal Bank of Scotland, has been hit by a malicious 'denial-of-service' attack on its payment and administration networks.
WorldPay, which provides online payment adminstration services to 27,000 clients in more than 70 countries, has been bombarded with computer-generated requests since yesterday.
In a statement, WorldPay says the attack was a coordinated effort by a third party to prevent customers from accessing the payment system and was identified within a minute of its occurrence.
WorldPay says it has resolved some of the problems caused, but is still trying to restore full services to customers.
Carolyn McAdam from WorldPay, told the BBC that payment systems have not been compromised by the attack and the company hopes to have the problem sorted out today.