Flooding on the M25 is ruining the Christmas getaway for thousands of people, as congestion worsens across the UK.
National Highways said a 10-mile queue built up due to the M25 being closed from junction 11 (Woking) to junction 12 (the M3) while standing water is cleared.
Two out of four lanes were later reopened.
Many drivers are battling a band of heavy rain which is moving north from southern England and Wales to southern Scotland and Northern Ireland throughout the day.
Junction four of the M20 westbound in Kent was closed for several hours on Friday morning after a serious crash on Thursday.
Vehicles were being diverted on to exit and entry slip roads, causing three miles of congestion and delays of at least 45 minutes.
The AA reported “severe congestion” on several motorway stretches on Friday, and said industrial action on the railways has added to the number of vehicles on the roads.
Among the locations with “severe congestion” are multiple sections of the M25, the M1 around Luton, the M4 and M5 near Bristol, the M5 north of Birmingham, the M60 west of Manchester and the M8 near Glasgow, according to the breakdown rescue company.
AA president Edmund King said: “Friday and Saturday will be the busiest on the roads with some 17 million trips each day.
“Then we’re expecting Christmas Day to be quieter with shorter local journeys.
“On Boxing Day traffic will pick up again with approximately 15 million trips as people head out to see friends and family.”
The RAC issued a “severe traffic alert” for the clockwise section of the M25 between junction seven for the M23 and junction 16 for the M40.
Many people are switching to road transport due to thousands of members of the Rail, Maritime and Transport (RMT) union at Network Rail walking out from 6pm on Christmas Eve, causing train services to finish at around 3pm that day.
An overtime ban is also causing major disruption to services by a number of operators on Friday, including Chiltern Railways, East Midlands Railway and South Western Railway.
Transport analytics company Inrix expects journey times by road to be around 14% longer compared with the same period last year.
The RAC urged motorists to carry out pre-journey checks on their vehicle before setting off, to reduce the chance of suffering a breakdown.
National Highways said almost 98% of England’s motorways and major A-roads will be fully open until the end of January 2 due to it completing and lifting roadworks.
