Lives could be at risk on a Hounslow estate because worshippers' cars are obstructing fire engines, residents have warned.
Worried householders raised the alarm after firefighters struggled to reach a blaze in Avondale Gardens just before midnight on Friday last week.
Thoughtless yobs had set fire to a trailer containing a portable toilet to be used for a community barbecue the following day.
Firefighters were able to put out the flames before they spread to neighbouring flats but residents fear they may not be so lucky next time.
They claim visitors to the mosque in nearby Wellington Road often double-park at busy prayer times during Ramadan, now taking place.
Alan Barber, chairman of Churchill Park Management, which runs the estate, said someone could have died had the fire started earlier when even more cars were around.
But Munir Rai, general secretary of the Hounslow Jamia Masjid & Islamic Centre, said the Imam appealed to worshippers every Friday to respect the temple's neighbours.
He added that he had asked Hounslow Council to open a road at the back of Heathland School for emergency access during busy periods.