One in five smartphone owners now does some of their shopping through apps, according to new research.

App shoppers spend an average of £30 a month on items from groceries and DVDs to train and cinema tickets, the study for marketing firm The BIO Agency found.

The company estimates £581 million per year is now being spent through apps by UK consumers who said convenience was the main attraction.

The BIO Agency's managing director Peter Veash said: "It's about convenience and simplicity when purchasing. You might not be at the shop or have access to a computer but you do have your phone with you.

"You can also compare prices easily. You can be in shop A and instantly check the price in shop B."

:: 3,000 people were surveyed by online research company OnePoll in March.