Motorists on the M25 faced hours of delays after two lorries crashed.
Huge tailbacks formed in the wake of the smash between junctions 30 and 31, with dozens of stranded drivers spending part of the night in an Ikea.
One of the lorries involved in the collision near the Dartford Crossing at about 14:35 BST on Tuesday overturned and ended up down an embankment.
No-one is believed to have been badly hurt in the crash, but the motorway was closed overnight.
The road reopened at about 05:45.
Among those stuck in the traffic was Olympic champion Dame Kelly Holmes, who told BBC Radio Kent she had been delayed for four and a half hours.
"I came from Leeds so I'm on 10-hour journey so far. We're on the slip road from Lakeside getting on to the M25," she added.
"I've been given chocolates by someone because I'm celebrating 14 years today of my 1500m win in Athens. I was meant to have a G and T tonight and now I'm stuck on the motorway with these lovely people."
Joanna Stratton, who was travelling from North Yorkshire to Uckfield, East Sussex, with her two-year-old daughter, said it took nine hours to travel just six miles.
She added: "It was one of the most horrific delays I've ever been in. There were motorbikes whizzing around, a man in a wheelchair had abandoned his car. It was so dangerous.
"Thankfully I'm still breastfeeding my daughter but I ran out of food and credit on my phone. Lots of people were sharing food and water, but I felt quite vulnerable."
Ben Glander also tweeted that he had been stuck for hours.
Dartford tunnel is a myth, been stuck in ikea car park for 2 hours now 👍🏻— Ben Glander (@ben_glander) August 28, 2018
Other people on social media reported being stuck at Ikea in Thurrock.
Esther Rollinson said on Twitter that she and her daughter had been "trapped in Ikea" due to the tailbacks from the crash for "5hrs +counting".
An Ikea spokeswoman said the store stayed open later to accommodate stranded shoppers.
"Following a road incident on the M25 yesterday afternoon, we understand that some people opted to wait in Ikea Lakeside rather than in their cars," she added.
"We accommodated them until around 11pm rather than our normal closing time of 10pm, with no-one staying the night."
After the road reopened, Highways England said some delays remained on the M25 clockwise approaching junction 30.
The Dartford Crossing consists of the Queen Elizabeth II bridge and two tunnels, linking Dartford with Thurrock, Essex.