Intense lightning strikes, thunderstorms and torrential rain have caused flooding in parts of London and the South East.
Red flood warnings were issued for parts of south-east London and Essex on Thursday as some areas were expected to recieve a month's rainfall in just a few hours.
London Fire Brigade (LFB) said it had received a day's worth of calls in just an hour and a half, and social media users reported being woken up by the fierce storms overnight on Wednesday.
The LFB received more than 300 calls reporting weather-related incidents including lightning striking property, flooded homes and businesses, and vehicles trapped by rising waters.
There have been reports of flooded streets as storms swept through, threatening disruption as voters head to polling stations.
Two polling stations in Kingston upon Thames, Shiraz Miraz and Devon Way have been forced to close due to flooding.
Kingston Borough Council has moved the stations to unaffected locations nearby.
James Brokenshire, MP for Old Bexley and Sidcup in south east London, shared a picture on Twitter of his local polling station imperilled by rising flood waters.
They were forced to tweet two separate messages urging people to only call in an emergency.
An LFB spokesman said: "Crews are being mobilised to incidents as quickly as possible but the Brigade is appealing to people to only call 999 in an emergency - where there is a risk to life or property.
"Between around 1.30am and 3am our control officers took over three hundred calls - around as many as they would receive in an average day."
In Bexley, East London, 20.5mm fell in one hour - close to half the June average. In Battersea, south west London, flood waters rose steadily after midnight, rising to knee height in ground floor homes on one street.
The Environment Agency issued four flood warnings covering rivers in Bromley, Sidcup and Basildon, with a further 22 flood alerts across the South East.
Showers were expected to ease by 10am on Thursday morning before returning with similar intensity from 2pm.
Met Office forecaster Luke Miall said: "If you draw a line from The Wash to the Isle of Portland, everything east of that is in the firing line.
"A band of showers is coming across the English Channel and moving north-eastwards, that will bring some heavy downpours and localised surface flooding. There's going to be a bit of hail in there too, so there's quite a lot going on.
"If you're in the South East, you definitely need your umbrella and possibly a pair of Wellington boots."
The heavy rain affecting the South East has affected transport in and around the capital with London Underground lines experiencing delays, part and full suspension due to signal failure and track flooding.
Gatwick Express southbound services have been suspended because of "poor weather".
South West Trains, Southern and TFL Rail are also suffering major delays because of the storms.
Many of London's roads were affected by localised flooding, including the North Circular which was closed at Waltham Forest
