Teenagers are being exposed to a high level of tobacco and alcohol images in online music videos, British experts warn.

Research from the University of Nottingham suggests girls aged between 13 and 15 are the most exposed.

The study, published in the Journal of Epidemiology and Community Health, analysed 32 of the most popular music videos during a 12-week period.

Experts estimated, using the census and their own data, that the average percentage of viewing of those videos was 22% for teenagers and 6% for adults.

They worked out the total number of depictions (impressions) of alcohol and tobacco in 10-second slots throughout the music videos seen by viewers.

Overall, the videos produced 1,006 million "impressions" of alcohol and 203 million of tobacco.

Trumpets by Jason Derulo, and Blurred Lines by Robin Thicke delivered some of the highest number of tobacco impressions, while Timber by Pitbull, and Drunk In Love by Beyoncé, delivered the most alcohol content, the study said.

increased risk of uptake of smoking and drinking

Dr Jo Cranwell, psychologist from the University of Nottingham, wants tighter measures put in place to protect children.

She is concerned about the potential for an increased risk of uptake of smoking and drinking among teenagers.

"Girls are looking at role models beyond their core family unit and their peers. They're looking at wider society and they're looking at celebrities on film," she said.

"They're very attractive and they lead very aspirational lifestyles and these young girls are looking to them to learn about how they should look and how they should behave"
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"The BBFC (British Board of Film Classification) should include portrayals of alcohol and tobacco smoking in their 'drug misuse' and their 'dangerous behaviours presented as safe age classification' criteria and at the moment they're not".

The BBFC says classification of content online is not required by law but many platforms use age ratings voluntarily.

The last review in 2013 public opinion was "clear that neither smoking nor alcohol were viewed as areas for concern for film classification".

Pupils aged between 14 and 17 at Oasis Academy in Enfield said they believed there should be more restrictions on music videos.

Alex Barlard, 17, said he did not believe the videos he had seen were "explicitly saying going out and smoke or drink" but he understood how some might be influenced.

He said: "When you look at the videos you associate their smoking and drinking with wealth and their power. They always look happy and always look they have good time with smoking and drinking".

Dimante Bribinskaite, 17, said she thinks younger people would be more affected by the images.

"I don't pay attention to these things and it doesn't affect me but they're kind of role models to younger people so when they see all these drugs and alcohol they want to be like them... it should be censored," she said.

In a statement YouTube said it has clear community guidelines.

"A user can filter out any 'potentially objectionable content that you may prefer not to see or don't want others in your family to stumble across' by switching on the 'Restricted Mode' on YouTube," it said.

"You can think of this as a parental control on YouTube, which can be 'locked on'".

"We display BBFC age classification information for UK music videos alongside implementing our own guidelines and safety features to ensure a great experience for users".

"We already display partner ratings for films but the music industry did not have a classification for videos before".