The son of Pink Floyd guitarist David Gilmour could be questioned by police after he admitted swinging from a Union Flag on the Cenotaph during the student protests.
Charlie Gilmour, 21, apologised for climbing the memorial to Britain's war dead in Whitehall, central London, saying he was "mortified" by his "moment of idiocy".
The Cambridge University history student said he did not realise it was the Cenotaph and felt "deeply ashamed" by his actions during yesterday's demonstration against higher tuition fees.
He only realised the significance of his actions after seeing pictures of himself in today's newspapers hanging from the flag with his legs dangling, a source said.
Scotland Yard said a 19-year-old man was held last night on suspicion of causing criminal damage in relation to the Cenotaph incident.
It is understood that this was not Mr Gilmour and there could be further arrests as the investigation progresses.
Mr Gilmour said in a statement: "I would like to express my deepest apologies for the terrible insult to the thousands of people who died bravely for our country that my actions represented.
"I feel nothing but shame. My intention was not to attack or defile the Cenotaph. Running along with a crowd of people who had just been violently repelled by the police, I got caught up in the spirit of the moment.
"I did not realise that it was the Cenotaph and if I had, I certainly would not have done what I did.
"I feel additionally mortified that my moment of idiocy has distracted so much from the message yesterday's protest was trying to send out.
"Those who are commemorated by the Cenotaph died to protect the very freedoms that allow the people of Britain the right to protest and I feel deeply ashamed to have, although unintentionally and unknowingly, insulted the memory of them.
"Ignorance is the poorest of excuses but I am sincerely sorry."
Mr Gilmour is on the books of modelling agency Select Model Management and has tried his hand as a journalist, but is now studying history at Girton College, Cambridge.
He is the son of writer and journalist Polly Samson and his father is the poet and playwright Heathcote Williams, her first husband. He was later adopted by the Pink Floyd musician when she remarried.
In an interview earlier this year, he talked about being bought two Savile Row suits before he headed off to university.
A Cambridge University spokesman said: "This incident took place outside term time in London and is a matter for the civil authorities."
David Gilmour's former bandmate Roger Waters lost his father in the Second World War and has written about his loss extensively throughout his career, including in a number of Pink Floyd songs.
The moving track When The Tigers Broke Free chronicles an attack on the Royal Fusiliers by German Tiger tanks.
Waters' father, Eric Fletcher Waters, served in the Fusiliers and died during Operation Shingle.
In the song, Waters describes finding a letter of condolence from the government. The song ends with his anguished cry: "And that's how the High Command took my daddy from me."
The cover of Floyd's album The Final Cut, which includes When The Tigers Broke Free, features a poppy and four Second World War medal ribbons.
Rock star Gilmour, who once donated more than £3 million from the sale of a house to the homeless charity Crisis, is admired as one of the world's finest guitarists and his Floyd album Dark Side Of The Moon is one of the biggest-selling records of all time.
He fell out with bass player Waters in the early 1980s but continued to tour and record under the name Pink Floyd.
Gilmour and Waters patched up their differences for a brief one-off Pink Floyd reunion in 2005 when the group played the Live 8 concert in Hyde Park.
The pair teamed up once more at an intimate charity benefit for just 200 people in the summer.Reuse content