The amount of money spent online via mobiles and tablets is set to grow almost three-fold to £23.1bn in the next five years.

According to research by Verdict, the rapid increase in tablet ownership will be the major driving force. Improving economic conditions and investment in mobile and tablet sites from retailers are also expected to spur growth.

Verdict analyst Matthew Rubin said: “Cannibalisation of spend has had a major impact in market sizes as mobile phones and tablets have become more mainstream shopping devices, often replacing desktops and laptops. Mobile phone spend has grown rapidly, though it remains relatively small, while tablet spend has grown from nothing to almost twice the size of mobile phone spend in just the two years to 2012, and that trend has continued into 2013.”

The research also found that 38% of online shoppers researched goods in-store before purchasing online.

“This appears to be a major concern for retailers with a physical presence” said Rubin. “However, with only 7% of mobile phone shoppers completing transactions in a store [via mobile] there is still a major opportunity to convince them to make the transaction through the store itself or through its own website.”