image copyrightGetty Imagesimage captionBuses and cars were left stranded when roads across London flooded on Sunday
Heavy downpours and thunderstorms have caused severe flash flooding in parts of London.
The fire brigade said it had taken about 300 calls – mostly about flooded basements or roads – on Sunday afternoon.
An amber thunderstorm warning is in place for much of south-east England, with 75 to 100mm (3in to 4in) of rainfall forecast in some areas.
Officials have advised against travelling in the hazardous conditions.
The Environment Agency issued two flood warnings for areas in London near Beverley Brook in Worcester Park and West Barnes.
'Canal, not a road'
A further 14 less severe flood alerts have also been issued, covering most of the capital and parts of surrounding counties.
Resident Chris Date tweeted a photo of a bus in Bakers Arms, Walthamstow, saying the flood water was "above the kerb".
"It's impossible to walk on the pavement. To get on that bus the water came up to my shins. This is a canal, not a road," he said.
image copyrightChris Dateimage caption'This is a canal, not a road,' said Chris Date
Many roads in the capital are closed because of the flooding, including the Blackwall Tunnel, the A12 and parts of the North Circular. There are long delays on other routes.
Eight Tube stations and one Overground station are also closed.
The Environment Agency and Fire Brigade have suggested people do not travel as conditions are hazardous.
A tweet from the Metropolitan Police Special Constabulary warned drivers they should not attempt to drive through floodwater if they find their route blocked.
Transport for London said the latest road information was available on its status updates page.
image copyrightGetty Imagesimage captionSome drivers were determined to make it through the flood
The Environment Agency said its staff were actively monitoring the situation and were prepared to respond if required.
The London Fire Brigade said it had not received reports of any threats to life but people should call 999 if in immediate danger.
Met Office meteorologist Steven Keates said parts of the south between south Suffolk and the Isle of Wight could be deluged by 100mm of rain in just a few hours on Sunday evening.
He predicted "pretty lively showers" from Norfolk to Bournemouth, with "torrential downpours, thunder and lightning and potentially some hailstones settling in the south."
Mr Keates said the storms were being caused by a "convergence" of air currents as warmth in the earth's surface from the recent heatwave rose into cooler air in the atmosphere.
image copyrightGetty Imagesimage captionFlash flooding took motorists by surprise
Forecasters had warned travellers starting their summer holidays to expect floods, thunderstorms and strong gusts of wind.
Days of extreme heat last week have given way to cooler temperatures and unsettled, stormy weather in places.
In Hampshire, the roofs of two semi-detached properties were severely damaged when they were struck by lightning on Saturday morning.
Temperatures are set to rise again from Monday, with London expected to hit 26C.