Severe weather warnings and flood alerts are in place across the country as another day of rain is expected.
Heavy showers will cover large swathes of the UK for another two days as an area of low pressure continues to move slowly across the country.
Wales, the North West, Yorkshire and Humber, the West Midlands, the East Midlands, the east of England, the South West and South East could all see as much as 25mm of rain in an hour.
Tuesday saw the rain put a dampener on proceedings at Ascot, soaking racegoers and forcing thousands of female guests wearing eye-catching head pieces to hide under umbrellas.
It also delayed the start of play at Queen's Club in London for the tennis Aegon Championships and the bad weather is unlikely to ease until Friday at the earliest.
The Met Office has put yellow warnings in place and advised that localised flooding and travel disruption are likely in the areas affected by the heavy rain.
The warnings are also in place for Thursday when lightning is an additional hazard.
The chief forecaster said: "Rising temperatures will trigger slow-moving heavy showers and thunderstorms.
"Once again, 15mm-25mm are likely to fall within an hour in scattered locations, bringing the risk of flooding, especially across urban areas."
The Environment Agency has issued 21 flood alerts indicating that flooding is possible, and warned people to be prepared.
The alerts cover areas in Cheshire, Merseyside, Derbyshire, Nottinghamshire, Northamptonshire, Oxfordshire, Buckinghamshire, the West Midlands, Staffordshire, Norfolk, Lincolnshire and north-west and north-east Greater London.