Northolt stand-off: Man barricaded in home may have petrol stockpile, police fear
Police believe the man may be experiencing mental health issues
Armed police are locked in a stand-off with a man who is feared to have a stockpile of petrol and other "combustible material".
Up to 80 people have been evacuated from addresses in west London as a precaution.
Scotland Yard said police were called on Saturday, shortly before 1am, to reports of concerns for an occupant and hazardous articles inside the address at Wood End Lane, Northolt.
Police are concerned for the man's wellbeing and believe he may currently be experiencing mental health issues, which could be exacerbated by police action or may make his behaviour unpredictable.
Officers have not attempted to enter the property out of "concerns for the safety of the man and responding officers," according a Met Police statement.
Police negotiators and armed officers remain at the scene and a 200m cordon has been set up. The Met says its priority is to bring the incident to a safe conclusion.
Chief Superintendent Paul Martin said: "Our aim is to bring this to a safe conclusion for everyone. I know that our operation has been ongoing for some time now and that it is causing disruption and inconvenience to local residents and the community of Northolt.
"I would like to thank them for their continued patience and cooperation.
"I can understand why people may be feeling frustrated or concerned. Their local officers are out on duty today to speak to local people, keep them updated and understand any concerns that they may have.
"The operation will continue for as long as is necessary and I would like to stress that we are doing all we can - using all our tactics - to end this incident safely."
There is no suggestion that the stand-off is terrorist related or linked to any other ongoing police operation or investigation.