Socks which were allegedly discovered with traces of explosives and found on a Briton as he tried to enter the UK have been shown to an Old Bailey jury.
Andrew Rowe, 34, of Maida Vale, London, was stopped trying to enter the UK via the Channel Tunnel in 2003.
The prosecution says the socks found in his luggage were rolled into a ball and attached to a pyjama cord, and may have used for cleaning a mortar bomb.
Mr Rowe denies four charges made under the Terrorism Act.
Three allege he had articles for use in terrorism and another charges him with making a record of information for use in terrorism.
On Friday, Detective Sergeant Terry Rockell told the jury how he had examined the sock ball at Scotland Yard on 16 November 2003 and had decided to send it to the explosives laboratory for testing.
He said the socks had been treated as part of Mr Rowe's luggage up to then, but he sealed it up in a plastic bag as evidence.
Sgt Rockell said he thought they were an ordinary pair of socks until he unravelled them and noticed the cord and became suspicious.
"My view at the time was that it may have been used to carry something," he said.
Earlier in the trial, jurors heard a search of Andrew Rowe's former flat in west London also uncovered a notebook with 20 pages of notes on how to use a mortar.
Mr Rowe converted to Islam in the mid-1990s, called himself Yusuf Abdullah and began to travel abroad a lot, the court heard.
He married in 1997 and had four children, but the couple later separated.
Mr Rowe was seen to visit the home of his estranged family in Birmingham in summer 2003, months before his arrest.
The trial continues.