Britain may have just experienced its wettest June since records began, but downpours forecast for this weekend could make last month seem positively arid. The Met Office has warned that more than a month's rainfall could fall today in parts of South-west England and Scotland, while already saturated areas could experience further flooding.

An area of low pressure to the west of the UK has brought in moisture from the Atlantic, disrupting travel across the country. In Cornwall today, some areas could see 15 to 20mm of rain in an hour, with 75mm (nearly 3in) expected in 24 hours in the South-west. The average for the whole of July is 69.9mm.

"It's falling on saturated ground, so there could be some surface water flooding," said Sarah Holland, from the Met Office, which warned that conditions may not improve in time for the Olympics.

"This year a protracted spell of hot, sunny weather looks very unlikely. In fact, inclement weather that has characterised June and early July will probably still be in evidence, although overall conditions are unlikely to be as bad," it said.

The MFEST music festival in Leeds, where Bob Geldof and Cher Lloyd were due to perform, was cancelled amid safety concerns.

Those with tickets to watch the British Grand Prix at Silverstone will have to contend with car parks that resemble Glastonbury-like mudbaths.

The worst-affected area yesterday was the North of England, which took the brunt of the storms . But severe weather warnings are still in place almost everywhere.

Yesterday the Environment Agency issued 124 flood alerts and 35 flood warnings calling for "immediate action", largely concentrated on the Midlands and North-west, covering about 11,000 properties.

By 2pm, 40.4mm of rain had fallen in Holbeach, Lincolnshire, while 27.6mm fell in Nantwich, Cheshire.