The number of online-only e-retailers operating in the UK has more than doubled in the past five years, a new study commissioned by the Royal Mail has revealed.

Around 15,000 new jobs have been created as a result of the influx of new start-ups since 2008, with overall employment in the sector rising by 25 per cent to 72,000 jobs over this period.

Businesses that operate exclusively online are growing at an average annual rate of 21.3 per cent, which is far better than companies that do not utilise the web.

The sector also contributed £2.2 billion to the economy in 2012 - up by 4.7 per cent on the previous year.

Managing director of Royal Mail Parcels Nick Landon said: "With continued growth in online shopping, we can expect more significant contributions to the UK economy in the coming years."

Of course, the emergence of web-based firms is having a major impact on the logistics industry - as firms need to rent out distribution centres - and this is inevitably leading to a shortage of available space in some parts of the UK.