Prominent Chinese dissidents accused British police on Friday of being heavy-handed after an exiled Chinese democracy activist and two Tibetan women were arrested at a protest during President Xi Jinping's state visit to Britain.

Shao Jiang, 47, was manhandled and arrested for peacefully protesting by stepping in front of Xi's motorcade on Wednesday evening ahead of a lavish London reception for the Chinese leader, according to fellow dissidents Wang Dan and Wu'er Kaixi.

Shao's home was raided and his computer equipment seized, said Wang and Wu'er, who like Shao were part of the student-led democracy movement in Beijing's Tiananmen Square in 1989 which ended in a bloody crackdown by Chinese troops.

At the same protest on Wednesday, two Tibetan women Sonam Choden, 30, and Jamphel Lhamo, 33, were taken away by police for attempting to unfurl Tibetan flags as Xi passed by, the dissidents and the women's lawyer said.

London police said they could not confirm the identity of those arrested, but said officers had detained a man and two women to prevent a breach of the peace and they had been further arrested on suspicion of conspiracy to commit threatening behavior.

The trio were bailed to return to a police station pending further inquiries.

"Reading the papers this morning I was disappointed to see a view by some that the Metropolitan Police Service were working to the bidding of the Chinese to suppress protest," said Commander Lucy D'Orsi in an unusually forthright police response to allegations demonstrations had been quelled.

"At all events this fundamental right to freedom of expression ... was available to everyone. In addition to the need to facilitate peaceful protest, there was a need to ensure a tight security operation for not only the Chinese President and First Lady but also our Royal Family and Prime Minister."

Xi's visit to Britain has helped seal an estimated 40 billion pounds ($60 billion) of business deals, but there have been small protests at events he has attended, with a large police presence to avert any trouble.

Bill Nash, the lawyer for the arrested Tibetans, said police had over-reacted and he had never heard of anyone being detained for the minor offense the women were accused of during his more than 40 years in practice.

"My money would be on zero in the past," he told Reuters.

Wang and Wu'er said the British government was putting trade over human rights.

"Speaking as victims of Beijing's systematic repression, we ... maintain that Britain's actions, both in welcoming Xi Jinping and arresting his opponents can only be described as shameful," they said in a statement from Taiwan where they live after fleeing China.

British Prime Minister David Cameron said this week Britain could have frank discussions with China about human rights because of its strong economic and trade links, while Xi said China attached "great importance" to the issue.

(Reporting by Michael Holden)