Other findings from the IAB UK Digital Adspend report, conducted by PwC, are that video advertising on the internet and mobile phones grew by 59% year-on-year to £202 million in the first half of 2014. Mobile video advertising, alone, grew 196% to £63.9 million – making it the fastest growing digital ad format.

Accompanying online data from YouGov revealed that almost three quarters ( 73%) of Britons online who own an internet-enabled device watched TV programmes online in the past six months; 72% watched short online video clips and 59% watched films online.

Those watching TV online average two hours 35 minutes a week, compared with one hour 50 minutes for online film viewers and 51 minutes for video clip viewers.

Tim Elkington, chief strategy officer at the IAB said: “A third of online viewers, particularly 35- to 44-year-olds, are watching more TV, films and clips online than a year ago. Consequently, video now accounts for £1 in every £5 spent on internet and mobile display ads. Average weekly viewing online amounts to 25 videos, four to five TV episodes and one film but what’s most interesting is that watching video on connected devices is becoming an increasingly social activity, like traditional TV. Half of people watching TV, films or video clips online do so with family members and three in 10 watch with friends.”