As druids gather at Stonehenge to mark the winter solstice, one of Britain’s top traffic experts has identified the Wiltshire location as the worst place for Christmas traffic.

Dr Graham Cookson, chief economist at transportation analysts Inrix, told The Independent that traffic on the A303 beside the neolithic stone circle will be “horrendous”.

“Most people heading from the South-east to the South-west, towards Devon and Cornwall, will venture down the A303, unfortunately.”

Just east of Stonehenge, the dual-carriageway Amesbury bypass goes down to a single carriageway. About two miles further west, the A303 meets the A360 at a roundabout which provides another source of congestion.

“There were 13 hours of tailbacks last Christmas,” said Dr Cookson. The only worse traffic jam was on the A5 near Watford Gap in Northamptonshire, following a serious accident on the M1 which closed the southbound carriageway.

Dr Cookson warned of “doubled and tripled journey times” on Wednesday, Thursday and Friday, particularly on the M25 around London, and the M6 in the Midlands and North-west.

On Thursday afternoon, Inrix predicts that journeys on the M6 southbound could take five times as long as normal, with peak delays from 2.30pm.

“People are creatures of habit, and they start journeys in the afternoon,” said Dr Cookson. “Any time from Wednesday afternoon onwards is going to be bad.”

The roads you should avoid this Christmas

Friday afternoon and early evening is predicted to see the highest density of traffic on Britain’s roads, when the normal rush at the end of the working week is augmented by people beginning the great getaway.

Dr Cookson advises motorists: “Set off in the morning, give yourself plenty of time and have lots of Christmas tunes.”

Highways England is lifting almost 400 miles of roadworks for the festive season, from 6am on Friday 22 December to 2 January. It says “almost 99 per cent of motorways and strategic A roads” will be free of works.

Meanwhile, the AA Trust is warning of the dangers of texting and driving with a short, hard-hitting film made in association with the FIA Foundation. Research shows that crashes are twice as likely from “text driving” as drink driving.

Traffic may increase from normal levels from 22 to 24 December because of rail strikes on Virgin Trains and CrossCountry.

As poor visibility continued in the London area, many more flights were grounded. London City was worst affected, with dozens of flights diverted, delayed or cancelled altogether.

Flybe diverted flights from Exeter and Belfast to Southend, as did British Airways from Malaga, while a Swiss flight from Geneva returned to its starting point.

At least 30 arrivals and departures at the Docklands airport were cancelled. Many flights are delayed by two hours or more.

At Heathrow, Aer Lingus, Lufthansa and Swiss have cancelled flights between Europe’s busiest airport and their hubs in Dublin, Munich and Zurich.

British Airways has made short-notice cancellations of domestic flights to and from Newcastle, Edinburgh and Aberdeen, and European services to Zurich, Geneva, Frankfurt and Amsterdam.

Aer Lingus also grounded a flight to Belfast City. The musician Andrea Begley said: “I was due to fly British Airways at 6.20 on Tuesday morning. I was rebooked onto the 11am flight with Aer Lingus today.” She was later re-booked on a flight to Dublin.

At Gatwick, the world’s busiest single-runway airport, some long delays are building. The overnight Virgin Atlantic flight from Orlando left the Florida airport over five hours late. WestJet’s service from Calgary was over three hours late, as was an easyJet flight from Amsterdam.