A drugs charity director is suing the police after he was searched during an operation involving sniffer dogs on the London Underground.
Release's Sebastian Saville, 56, claims police breached his human rights during the incident at Camden Town station in June 2008. Nothing illegal was found.
Release claims Mr Saville was a victim of "funnelling", whereby random targets are forced into the path of dogs.
British Transport Police said they were investigating the allegations.
Mr Saville - a reformed heroin addict - said he was on his way to work when his route was blocked by police officers and a dog positioned at the top of an escalator.
The dog barked, prompting officers to search Mr Saville's pockets.
'Unreliable and ineffective'
"Because of this it is claimed that Mr Saville was therefore unlawfully detained and searched," a spokesman for the charity said.
"Release argues that these actions constituted a breach of Mr Saville's fundamental human rights to freedom of movement and respect for private life, as well as constituting a trespass to his person."
The charity is asking the High Court to make a declaration that the use of sniffer dogs as a means of establishing reasonable grounds for a search is unlawful.
According to Release, which provides free specialist advice and campaigns for changes to UK drug policy, sniffer dogs are an "unreliable and ineffective police method".
The charity is campaigning for more regulation of their use.
Mr Saville, from Camden, north London, said: "The police have powers to stop people where they have probable cause, but to search for probable cause using dogs when dogs are wrong four times out of five is, I believe, not right."
A British Transport Police spokesman said: "We use a range of tactics including drugs dogs, explosive search dogs and metal-detecting arches to keep passengers safe.
"We are aware of the allegations made by Mr Saville and we are investigating them."
Source - http://news.bbc.co.uk/1/hi/england/london/8182594.stm