According to stas from Internet market research outfit Nielsen Online, eBay subsidiary PayPal had 5.20 million unique visitors to its site in January - nearly five times as many as the next most popular payments outfit, Royal Bank of Scotland owned WorldPay, which had 1.07 million unique visitors.

Independent contender Protx received 426,000 visitors whilst new entrant Google Checkout attracted 301,000 unique visitors.

The PayPal site also came top when compared to other financial Web sites and was followed by MoneySupermarket.com which attracted 3.66 million unique visitors, Barclays with 3.02 million visitors and Lloyds TSB with 2.99 million site visitors.

Commenting on the findings, Alex Burmaster, European Internet analyst, Nielsen Online, says: "PayPal continues to be by far and away number one. It has started 2008 by consolidating the lead it held throughout 2007 as the most popular financial Web site in the UK. PayPal had almost five times more unique users compared to the next online payment provider, despite new entrants in the market such as Google Checkout."

PayPal processed $47 billion (£24 billion) of payment volume globally in 2007 and over 100,000 Web sites now accept the service.

A US study released by Javelin Research & Strategy in September 2007 predicted that alternative payment methods - such as PayPal - will increase to gain 30% of all online transaction volume by 2012, up from 14% in 2007. Javelin said consumers view alternative payment methods as a trusted and viable way to pay for online purchases.

A separate poll conducted by interactive marketing firm Brulant last year found that around 30% of US online retailers now offer customers the option to use services such as Google Checkout, PayPal and Bill me Later - which is a 25% increase since February 2007.