Guns and a grenade have been found in a house in Hampton, but have now been removed.
A 60-year-old man was arrested this afternoon (February 1) and was taken to a south London police station.
Parts of Hatherop Road and Priory Road were closed at about 12.45pm, but have now been re-opened.
Jamie Wingate, who works at the Royal Mail in nearby Rosehill, said he overheard officers talking about "bringing in the army".
It is likely this will refer to a bomb disposal squad.
He also said the house in question and houses either side were evacuated by police.
The corner of Hatherop Road and Priory Road, circled in red
Metropolitan Police said: "On Wednesday, 1 February police attended a residential address in Hatherop Road, TW12 at around 10:09hrs, following a concern for the safety of a resident.
"On arrival officers found a quantity of firearms and a suspected grenade.
"Specialist officers are at the scene and assessing the items. A cordon remains in a place while this assessment takes place.
"A 60-year-old man has been arrested under the Firearms Act and taken to a south-London police station.
"Local road closures remain in place. The incident is ongoing."
Petra Sale, a Hampton ward councillor who also runs Asters Florist in nearby Station Road, said one of her delivery drivers was unable to drive down Hatherop Road because of a police cordon.
Samantha Smithers tweeted this photo of Hatherop Road
Earlier this afternoon a resident, from Hatherop Road, reported that the area was "crawling with police".
Hampton councillor Suzette Nicholson said: "I came up here to see if everything was ok.
"There's a house closed off and there's a police man outside. He said that local residents aren't at risk of coming to any harm."
- Are you in Hatherop Road? Call the newsdesk on 0208 722 6313 or email rachel.dickerson@london.newsquest.co.uk
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