The ritual August holiday exodus from cities to the sea stranded Italian motorists in 20-mile traffic jams at the weekend while temperatures soared above 38C (100F).

Traffic on motorways and country lanes was reduced to a standstill as an estimated 20m people simultaneously tried to get away from it all.

Civil protection crews distributed bottles of water and medical help to families stuck for up to six hours in the weltering heat, which frayed tempers and made babies cry.

In Milan, those who left home at 4am to beat the rush discovered five-mile jams already waiting. By 11am thePadua-Venice stretch of the A4 was blocked for 20 miles.

Motorways in central and southern Italy were paralysed all the way to the peninsula's toe, and there were delays of several hours to board ferries to Sicily and Sardinia.

Fiumicino airport, Rome, reported a 14% increase in the number of air travellers compared to the first Saturday of August last year.