Teenager charged over explosives in London Tube probe

London: British police today charged a 19-year-old man with making or possessing explosives after a suspicious item was found on a London Underground train last week.

Damon Joseph Smith was charged a week after the item was found on a train at North Greenwich station, which serves the O2 entertainment complex in southeast London.

He is due to appear in custody at Westminster Magistrates' Court tomorrow.

London's Metropolitan Police allege Smith "unlawfully and maliciously made or had in his possession or under his control an explosive substance with intent by means thereof to endanger life or cause serious injury to property in the United Kingdom".

The charges relate to a day between October 18 and October 21, when Smith was arrested by armed police on a busy shopping street. An electric stun gun was used during the arrest, but no shots were fired.

A police spokeswoman would not confirm whether the explosive substance was a viable bomb and told AFP that Smith's alleged offence was not terrorism-related.

Charges were brought after a London court on Saturday granted police permission to hold Smith, from southeast London, for an additional six days for questioning.

Earlier in the investigation police said they were keeping an open mind regarding any possible motive. Police are not currently looking for anyone else in relation to the investigation.

On Saturday, officers went to an address in Newton Abbott, around 270 kilometres southwest of London, as part of the inquiry and "found an item they deemed suspicious", Scotland Yard police headquarters said.

The officers evacuated the address and established a 200-metre cordon around it, but the item was later declared "not viable".

A controlled explosion was carried out on the suspicious item found on the Tube network and security was stepped up on the London Underground in a bid to reassure the public.

Britain's current national terror threat level has been set at severe -- the second highest of five -- since August 2014, meaning an attack is considered highly likely.