Psy and Nick Clegg trend in YouTube's annual round-up

YouTube has posted its own tribute to some of its most watched clips

Gangnam Style singer Psy, the X Factor's Lucy Spraggan and Deputy Prime Minister Nick Clegg have all made it onto YouTube's top 10 UK "trending videos" of 2012.

The list is based on clips that saw the biggest leaps in traffic over the year.

The Liberal Democrat leader appears in a video which took his apology for a u-turn on tuition fees and turned it into an auto-tuned song with the chorus "I'm sorry, I'm sorry, I'm so, so sorry."

Six of the 10 clips were music-based.

Other examples included a post by Walk of the Earth which featured a group of five musicians playing a cover of Goyte's Walk Off the Earth while sharing a single guitar, and market trader Muhammad Shahid Nazir singing about seafood sold from his East End London stall.

The £1 Fish clip made Mr Nazir and his "song" famous. Pop star Alesha Dixon and US record producer Timbaland subsequently created their own cover versions - both of which have also been uploaded to the Google-owned sited.

Other clip creators took advantage of YouTube to help their videos go viral for more serious purposes.

US activist group Invisible Children attracted more than 100 million global views in six days for Kony 2012 - a video about the use of child soldiers in Uganda by the Lord's Resistance Army movement.

The top 10 also features footage of skydiver Felix Baumgartner travelling faster than the speed of sound during his descent from a balloon 128,100ft (24 miles; 39km) above New Mexico.

In addition, the BBC squeezed into the list with close to 1.7 million views for director Danny Boyle's Olympics film showing James Bond escorting the Queen to the opening ceremony.

Romney rap

Only four of the UK's top 10 trending clips made the global list.

South Korean pop start Psy managed to headline both.

But the international list was also enlivened by a satirical face-off between two rappers impersonating US President Barack Obama and his Republican challenger Mitt Romney; and Facebook Parenting - a father's take on his relationship with his 15-year-old daughter in the age of social media.

Most of the clips feature advertising either as pre-roll video or overlaid ads - and one industry watcher noted that the mix of high-end and cheaply made clips will have helped boost the firm's bottom line.

"User generated content continues to be at the heart of YouTube's success -and professionally made videos still only account for a fraction of the material on the site," Ian Maude from Enders Analysis told the BBC.

"It's all very fragmented and this material is fairly hard to monetise - but we are seeing more companies and organisations using it as a distribution channel.

"Google is trying to encourage that with its 'professional content' and a more TV-like structure to attract more advertising, and it's working. We think YouTube will have generated about $3bn (£1.8bn; 2.2bn euros) in gross revenue this year and will make more than $4bn in 2013."