Coldplay could face a multimillion-pound copyright lawsuit after being accused of plagiarism on their new album.

The British band has denied stealing the melody to the title track of their Viva La Vida Or Death And All His Friends album from obscure US group Creaky Boards.

Their singer has alleged Coldplay frontman Chris Martin took the music from his ironically named track The Songs I Didn't Write after hearing them in concert.

Rock royalty: Chris Martin of Coldplay denies stealing the tune to one of his new songs

In a video posted on the video-sharing website YouTube, Andrew Hoepfner accused Mr Martin of artistic theft.

'We were flattered when we thought we saw Chris Martin in the crowd,' said Mr Hoepfner of his New York gig.

'He seemed pretty into it... Maybe TOO into it?'

The clip was first posted on Sunday as Viva La Vida  went straight to No.1 after selling 300,000 copies in three days.

It has now been watched by nearly 300,000 people, many thousands of whom had typed comments remarking upon the various similarities between the two tracks.

In an industry where even small chord sequences can become the subject of costly copyright disputes, allegations of plagiarism can leave both the finances and reputation of musicians badly damaged.

Coldplay yesterday responded with a vigorous denial.

Pop paupers: Creaky Boards frontman Andrew Hoepfner, front, says his track The Songs I Didn't Write was stolen after Chris Martin attended a New York concert

'We totally refute their claims, and there are two facts that make it easy to disprove them,' said the band's spokesman Murray Chalmers.

'First, on the night in October when the band say Chris Martin was watching them, he was actually working at the Air Studio in London, and we can prove that.

'Second, even if he had been at the gig, Viva la Vida was written and demoed seven months before the night in question, so it couldn't possibly have been copied.'

Sources close to the band said they were unlikely to pursue legal action against Creaky Boards since it would 'look bad' to start a David versus Goliath lawsuit against a group of young musicians.

However, despite Mr Hoepfner's claim of theft, the video clip has succeeded in gaining a new following for his band, and was driving traffic to their MySpace page.

The YouTube video concludes: 'I wish Coldplay the best of luck. If they ever want to collaborate, I've got some microphones we could use in my bedroom.'

Watch Andrew Hoepfner make his allegation below...