Commercial broadcasters have renewed their attacks on YouTube and Facebook with a new study highlighting the power of television advertising compared with the tech giants.

Research commissioned by Thinkbox, an industry group backed by ITV, Channel 4, Sky and others, found that television advertising generates £4.20 in profit for every £1 spent.

That compares with £2.35 for online video and and 84p for online display advertising. Print was the second most efficient advertising medium, adding £2.43 to the bottom line for every £1 spent.

The study was carried out and audited independently by marketing analysts at Ebiquity and Gain Theory, based on 2,000 advertising campaigns.

Thinkbox said the findings showed that television advertising was under-appreciated by brands. While it accounted for 71pc of profit generated by the campaigns, it received only 54pc of their budgets.

Commercial broadcasters are attempting to slow the flow of money online. YouTube and Facebook especially have been targeting television advertisers with some success, although recent controversies over brands appearing alongside inappropriate videos prompted big companies including HSBC and Tesco to stop spending on YouTube.

Matt Hill of Thinkbox said: “Businesses are under immense economic pressure and marketers have to justify everything they spend.

“It is crucial that we constantly refresh and update our understanding of what different forms of advertising contribute so that marketers are spending wisely.”

The UK television advertising market is expected to contract by 2.7pc this year before returning to growth in 2018, according to the Advertising Association.