This weekend is set to see a huge spike in road journeys as commuter traffic is swollen by last-minute shoppers and people setting off on Christmas getaways.
Friday is expected to be the worst day for traffic with an estimated 2.8 million journeys taking place but Thursday is expected to see around 2.5 million individual trips as well.
Ahead of the festive free-for-all, traffic specialists Inrix have issued a list of the roads expected to be worst affected, with some sections of road expected to see up to three-hour delays.
Sections of the M6, M25 and M40 are all expected to see delays of between 80 and 180 minutes, with other roads seeing journey times extended by between eight minutes and an hour, according to Inrix and the RAC.
The northbound M6 between junctions 15 and 25 is expected to see the very worst delays with a predicted hold-up of 181 minutes on Thursday December 20. Congestion is predicted to last throughout the day, with experts advising that the quietest time to travel will be after 8pm.
Friday 21 will see the worst hold-ups on the M40 with northbound traffic experiencing 35-minute delays and southbound drivers facing almost two hours of delays.
Hour-long delays are also expected on the same stretch between Aylesbury and the M42 on Saturday 22, with similar delays again on the M6 between J15 and J25.
The anticipated jams will be compounded by extensive disruption to the rail network â€“ both planned and unplanned â€“ that could force more people onto the roads. Strikes are likely to affect routes run by Northern Rail and South Western Railway, and Network Rail is planning extensive engineering work on lines running into major stations including London Paddington and Victoria.
INRIX data scientist Joshua Kidd said: â€œOur data shows that compared to a normal day, Thursday December 20 will see the biggest increase in cars on the road.
â€œWith most drivers setting out mid-morning, traffic will become heavier over the course of the afternoon and stay congested into the evening. But itâ€™s not just those off to see family and friends – commuters, last-ditch shoppers and online deliveries will contribute to clogging the roads.â€
RAC Patrol of the Year Mark Souster added: â€œThe run-up to Christmas is traditionally a very busy time on the roads and for us as patrols, and 2018 looks to be no exception.
â€œItâ€™s vitally important every driver planning a trip gives their car a once over to make sure itâ€™s up to the job, as a single breakdown can bring some roads to a grinding halt, slowing down the Christmas getaway for all of us.â€
While this weekend is set to be a busy one, next week that will see the very worst of the traffic. Inrix/RAC data estimates that traffic is likely to peak on Boxing Day when some 6.8 million individual trips will be made.
In full: roads expected to be worst affected
Region Location Peak congestion from Predicted travel time (mins) Total delay (mins) 19th December Greater London M25 Clockwise J20 (Hemel Hempstead) to J28 (Chelmsford) 3.30pm 114 79 Greater London M25 Anticlockwise J20 (Hemel Hempstead) to J11 (Woking) 3.15pm 86 58 North West England M62 West J27 (Batley) to J18 (Manchester ring road) 6.30pm 76 48 South West England M5 South J16 (Thornbury) to J19 (Portishead) 5.30pm 41 31 North West England M60 clockwise J6 (Sale) to J19 (Manchester) 3pm 44 28 20th December West Midlands M6 North J15 (Stoke-on-Trent) to J25 (Wigan) 12.30pm 229 181 Greater London M25 Anticlockwise J20 (Hemel Hempstead) to J11 (Woking) 5pm 131 86 South East England M20 East J8 (Lenham) to J13 (Folkestone) 7.30pm 82 56 South East England M3 South J6 (Basingstoke) to J13 (Bournemouth) 3pm 65 44 Greater London M25 Anticlockwise J4 (Bromley) to J30 (London E & C) 2.30pm 54 39 21st December West Midlands M40 South (M42) to J8A (Aylesbury) 2.30pm 157 110 West Midlands M40 North J8A (Aylesbury) to M42 12pm 84 35 West Midlands M6 South J20 (Macclesfield) to J16 (Newcastle-under-Lyme) 5.15pm 58 33 West Midlands M5 North J4A M42 to Ray Hall interchange 7.45pm 39 21 Scotland M8 West J12 (Riddrie) to J29 (Paisley) 12.15pm 21 8 22nd December West Midlands M40 North J8A (Aylesbury) to M42 5.45pm 105 61 West Midlands M6 North J15 (Stoke-on-Trent) to J25 (Wigan) 7.15am 104 59 South West England A303 West Salisbury Road to A350 2.45pm 46 19 West Midlands M6 South J20 (Macclesfield) to J16 (Newcastle-under-Lyme) 12.30pm 43 18 West Midlands M5 North J4A (M42) to Ray Hall interchange 6pm 31 14