Scores of homes and hotels on the Isle of Wight were evacuated after flash floods. The High Street at Lake, near Shanklin, was under two feet (60cm) of water.
Police in Hampshire answered more than 120 calls to fire alarms set off by the storms. In Berkshire, the fire brigade was receiving 20 calls for help a minute at the height of the storm.
Elsewhere major roads were affected by flooding and driving conditions were extremely hazardous. The M27 near Portsmouth was under water and driving on the M3 in Hampshire and Surrey was almost impossible.
Firemen described driving on the M4 between Slough and Reading as 'like navigating the River Thames'.
The A4 was closed between Hungerford and Marlborough. Houses in Hampshire, Surrey, Buckinghamshire, Oxfordshire, East Sussex, Dorset and Berkshire were hit by lightning. One house in Chipping Norton, Oxfordshire, was left with a 2ft (60cm) hole in the roof. Elsewhere firefighters dealt with small fires.
In Battle, East Sussex, electricity supplies were cut off and the town was blacked out.
The storm brought a shock to 30 businessmen at a health farm when more than five inches of cold water cascaded into the Turkish bath at a health farm in Swindon, Wiltshire. Gladys Barr, 28, manageress, said the steam room became a 'paddling pool'.
Seven children were among 22 people taken to hospital after an earlier accident involving 16 cars and a lorry on the M25 London orbital motorway near Enfield, north London.