Mr Wood says police should not target peaceful protestors
A legal bid to challenge the power of the police to use surveillance against peaceful protesters has been launched at the High Court.
Andrew Wood, from Oxford, claims he was harassed by the Metropolitan Police for campaigning against the arms trade.
He says they breached his human rights by photographing and questioning him even though he had not broken the law.
The Metropolitan Police says its actions were "justified and proportionate".
The judicial review could decide if police are legally entitled to gather information on people even if they do not commit an offence.
Mr Wood told BBC Radio 5Live: "It was very intrusive."
Mr Wood, who was then a press officer at Campaign Against Arms Trade (CAAT), attended the 2005 annual meeting of Reed Elsevier, a company which organises arms fairs.
He had bought a share in Reed Elsevier in advance and therefore says he was entitled to attend the meeting as a legitimate shareholder.
He says he wanted to ask the board of directors about the company's recent purchase of another arms exhibitioner Spearhead.
Martin Westgate, representing Mr Wood, told the High Court: "He asked one question. His behaviour was completely unexceptional, although there was a small disturbance and two other people were ejected."
Mr Wood says that when he left the meeting officers from the Metropolitan Police breached the Human Rights Act by photographing, questioning and following him and six other campaigners.
And he says they committed further breaches by storing the photographs on police computers even though none of the protestors was arrested or charged with any offence.
"The behaviour of the police was oppressive, bordering on harassment," Mr Wood said.
"A police surveillance operation like the one I experienced risks a real prospect of a chilling effect on democratic participation."
Lawyers representing Met Police Commissioner Sir Ian Blair insist that any interference with Mr Wood's human rights was at a very low level and in pursuit of the legitimate aim of preventing crime.
In a letter responding to Mr Wood's allegations, the Metropolitan Police said they felt there was "a likelihood that demonstrators may well engage in criminal acts".
"It was therefore considered necessary to photograph and if possible, identify those who attended the AGM in order to protest in case they had either caused disruption or planned to do so in the future," it said.
The intention was, the police added, "to do no more than remind participants of the need to comply with the law".
But Mr Westgate said: "It may well be that a group of police officers may consider this was behaving in an entirely amicable, non-intimidatory way, but that is not the way it appears on the receiving end."
Recently, CAAT played a major role in winning a High Court ruling that the government acted unlawfully when it stopped a corruption investigation into BAE Systems' Al-Yamamah arms deals with Saudi Arabia.
The hearing is scheduled to last for two days.