British holidaymakers have been warned to allow several hours to get through the Channel border at Dover and Folkestone, as the UK and France continue to argue over who is to blame for the gridlock.
A Port of Dover spokesman said there is still a "long way to go" to clear the backlog of vehicles on the M20 in Kent and people stuck on the road have told of queue times of at least seven hours approaching the Eurotunnel at Folkestone.
And through the day, summer getaway congestion spread across the country affected more key routes, according to the AA.
In Dover, lines began forming at around 4am. And some 17,215 cars had been processed in Dover by lunchtime - far exceeding Friday's 8,500.
One family, with three children in the car, said they were "fed right up" after being stuck for nearly 11 hours at Dover.
Angie Emrys-Jones, 46, from Cornwall, said: "There were rows and rows of standstill traffic as far as we could see since we arrived.
"No police marshalling, (we are) exhausted and hot. Rumours going around the cars were rife... 'The whole system is down and each car was having to be checked in by hand' (or) 'they've stopped all trains for the day'."
P&O Ferries has been recommending travellers allow up to four hours just to pass through checks, admitting some could end up missing their scheduled departures, but would be allowed on the next one available.
One family who spoke to Sky News said they had being queuing for the tunnel for three hours - and only had a mile left - but it was expected to take another four hours to reach the end of the queue... and then there would be long delays getting through border control, too.
One haulier group Logistics UK told how some of their lorry drivers had waited "in excess of 18 hours" to cross the Channel.
French MP for Calais, Pierre-Henri Dumont claims the chaos is down to increased passport checks after Brexit and a lack of investment in Dover's port.
The government argues French border staff need to raise capacity.
"The Port of Dover is too small for this amount of people," Mr Dumont told Sky News, refuting British claims there were not enough French staff at the border on Friday.
"Two years ago the Tory British government decided not to give money to the Port of Dover to increase the number of kiosks there for French police.
"Because of Brexit we need to have more checks on passports, so this is what your future will look like for years to come if you take no action."
On the dispute over who is at fault, he said of UK politicians, particularly those involved in the Tory leadership contest: "They are not talking about facts, they are talking about fake news, blaming French authorities for a problem that is not on us."
'Appalling' start to summer holidays
Foreign Secretary Liz Truss has blamed French authorities for Friday's "unacceptable" delays, calling on them to bring in more staff to handle the demand.
"We need action from France to build up capacity at the border to limit any further disruption for British tourists and to ensure this appalling situation is avoided in future," she said.
Speaking to Sky News on Saturday morning, when lines started forming around 4am, Conservative MP for Dover Natalie Elphicke described Friday's disruption as "appalling".
"It was a dreadful start to that summer getaway yesterday and an appalling situation for residents in Dover too. There simply weren't enough French border police," she said.
"Today I am hearing the French workers have turned up and they are expected to be manning the booths at capacity but there will be a knock-on effect as there always is when there is an issue that has happened at the ports."
Operation Brock, which redirects freight traffic off the M20 motorway to allow more lorries to get through, is resulting in further delays for those trying to get away on holiday.
More than 100 fixed-penalty notices have been issued in the past 24 hours for non-compliance with the rules for freight drivers, Kent Resilience Forum (KRF) said.
EU-bound hauliers have been warned that not complying with signs to follow the traffic management system and trying to jump the queue risks a £300 fine as well as removal to the back.
On Saturday, a Port of Dover spokesperson said: "The Port of Dover is relieved that French border staff (Police Aux Frontieres) have been fully mobilised at French border controls in Dover (known as 'juxtaposed controls') on Saturday morning in order to get holidaymakers and freight vehicles moving and to relieve the disruption on the Dover and wider Kent community."
They added: "Passengers should keep in touch with their ferry operators for the latest information on their sailings.
"We will, together with our ferry operators, support the efforts of all partners to get people on their way as quickly as possible."
Transport Secretary Grant Shapps said he is "working closely" with the French transport minister Clement Beaune, adding: "I welcome his commitment that both Britain and France will work closely to minimise further disruption so people can get away quickly."
Mr Beaune re-tweeted the statement on Twitter.
Saturday was expected to see the peak of summer holiday traffic.
Jack Cousens, head of roads policy for the AA, said: "The summer getaway is now in full swing and the major holiday routes are starting to fill.
"The South East has been overwhelmed with travellers hoping to hop onto the continent with ease, but that has rapidly turned into a nightmare.
"One that is now being shared by the locals as drivers try to find alternative roads so they can keep the wheels turning."
Away from the ports, the biggest delays have been on the M25, M3, M4, M5, M6, A303 and A31.
This afternoon, the AA said most traffic has flushed through, but "the next big challenge facing the South East is clearing the backlog of freight that has been queuing".
And a spokesperson said they expected to tomorrow to be much quieter on the roads.