Meanwhile, the son of Pink Floyd guitarist David Gilmour has apologised for a "moment of idiocy" which saw him climb the Cenotaph during the protests.
Charlie Gilmour was pictured swinging from the Whitehall memorial on a Union Jack.
"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," he said.
"I feel nothing but shame. My intention was not to attack or defile the Cenotaph.
"I did not realise that it was the Cenotaph and if I had, I certainly would not have done what I did."
Mr Gilmour may face charges over his actions.
Scotland Yard says a 19-year-old man was held last night on suspicion of causing criminal damage in relation to the Cenotaph incident but that was not Mr Gilmour.
Police said there could be further arrests as the investigation progresses.