Facebook brings autoplay adverts to UK
Facebook is introducing automatically playing video adverts to the UK.
The social network initially trialled the features in the US and the first ads are expected to play in Britain within weeks.
They will run without sound unless clicked on and, on mobile devices, will load only over wi-fi.
Facebook will hope to continue its recent success in increasing ad revenues, having seen a significant rise in the past 12 months.
The company said on Wednesday that it would be introducing the ads with a "limited group of advertisers" in the selected countries, including the UK, Australia and France.
It is also unveiling the feature, called Premium Video Ads, in Brazil, Canada, Germany and Japan. But Facebook did not reveal the companies that would be advertising.
Facebook said the introduction would be tentative and, while the first ad could appear in June, most would not run until later as it attempted to control quality.
"We'll roll out Premium Video Ads slowly and monitor how people interact with them," said Facebook in a statement.
"This limited introduction allows us to concentrate our efforts on a smaller number of advertisers with high-quality campaigns."
Each video advert will be 15 seconds long and will start playing without sound as it appears on the screen.
The ads will stop playing if users scroll past them. But, if people tap or click on the video, it will expand into a full-screen view and sound will start, Facebook said.
Facebook's figures for the first quarter of 2014 showed it made $2.27bn (£1.34bn) from advertising, an 82% increase on the same quarter last year.
And it said that mobile ads, which have generated very little return until recently, represented about 59% of the company's total advertising revenue for the quarter.
That was up from about 30% of advertising revenue in the first quarter of 2013.
Jeremy Arditi, UK managing director of online video ad tech company Ebuzzing, said it was a good move for Facebook.
But he said: "Most online video ads annoy people and interrupt their browsing experience," adding that industry estimates indicated that "around 60% of online video ads don't get seen".
He pointed out that there was an element of risk to brands, which could conceivably end up appearing next to inappropriate content posted by other users.