Smartphone shopping is common in the UK, and commonly in-app
Consumers in the UK are more likely than most to shop via their smartphones. Indeed, eMarketer forecast that UK retail ecommerce sales will exceed £67 billion ($102 billion) in 2016, fueled by impressive growth in smartphone-based buying.

April 2016 data from comScore MobiLens showed that smartphone mcommerce buyer penetration in the UK was higher than elsewhere in the EU-5, with 33.8% of smartphone users ages 13 and up having made a smartphone purchase.
So the consensus view is that smartphone shopping is widespread in the UK, at least when compared to the rest of Western Europe. What was particularly striking in the comScore MobiLens research, though, was the fact that UK smartphone mcommerce buyers were also far more advanced in their in-app buying habits.
According to the research, 59.3% of smartphone buyers in the UK made purchases via apps. Only their counterparts in Germany had a rate above 50%—just slightly, at 52.1%—while the rest of the EU-5 saw proportions in the low 40s.

Given the generally stronger predilection to shop via smartphone in the UK, retailers may want to take note of the fact that apps are as influential here as is the mobile web—only slightly more said they had made smartphone buys this way, at 60.5%.
eMarketer estimates that 57.0% of smartphone owners in the UK will make at least one mobile purchase during 2016, up from 55.0% in 2015.