Britons have spent more than £100bn online since 1995, according to online retail research group IMRG.

Online sales for April rose 55 per cent, the largest rise since December 2003 when Christmas shopping sent sales soaring.

Travel is still the most popular category for online spending, accounting for £7bn of all spending last year, but sales of electrical goods, clothing and groceries are rising rapidly.

Retailers that embraced online sales early are reaping the benefits; Tesco is now the UK’s fourth largest internet retailer, with Tesco.com processing almost £1bn of grocery sales and generating profits of £56m.

Only Amazon, Dell and Argos rank higher, with Argos easily transferring its catalogue shopping online to cash in on the boom.

And John Lewis Direct is reporting good growth in the first quarter of the year, says head of web selling David Walmsley, with a 45 per cent increase in online sales.

Others are catching up, with Sainsbury’s announcing last week that online sales have increased more than 40 per cent and plans to double the number of stores offering online services from 100 to 200.

Reaching the £100bn mark is an astonishing landmark, says IMRG managing director Jo Evans.

‘It has been obvious for a couple of decades that a secure, networked consumer marketplace would arrive and be popular but the growth has been meteoric,' she said.

‘April’s online sales were worth about the same in one month as London’s West End takes in a year.’

The spread of high-speed broadband has been one of the major factors in the rising popularity of online shopping.