There are warnings of delays at the Port of Dover this weekend as holidaymakers and lorry drivers try to get to France.
The AA motoring group issued its first amber traffic warning for Friday and Saturday. Tens of thousands of families were gridlocked on the way to the port last weekend.
But what has been causing the disruption?
The French authorities have blamed the delays on the additional checking and stamping of British passports.
The UK and France have "juxtaposed" controls, which means checks to enter France are done at Dover and other British ports by French officials, while checks to enter the UK are done in French ports by UK officials.
Before Brexit, there was much less need for rigorous checks at the border, because of freedom of movement. This is the automatic right for EU citizens to move freely within the European Union.
Since Brexit, UK citizens no longer have this right (and neither do EU citizens coming to the UK).
"Prior to Brexit there was a deemed right of entry - we weren't in Schengen [the agreement which removed checks at shared borders] but there were still very minimal checks," says Lucy Morton, from the ISU - the union for borders, immigration and customs staff.
But now French officials have to stamp passports and carry out a number of checks including:
- checking the identity page
- checking the traveller hasn't been to the EU for more than 90 days in the last 180 days
- checking there is at least three months left on the passport
- checking that the passport was issued less than 10 years before the date of entry
- checking the traveller has a return ticket
- checking proof of insurance
- asking whether the traveller has enough money.
Checking each person can take up to a minute, rather than a few seconds, transport expert Simon Calder told BBC Breakfast.
A Downing Street spokesman said the travel disruption was caused by a number of factors and not "necessitated by leaving the European Union".
He added: "It is obviously for individual governments to decide how to carry out checks at the border, our view is these should be done proportionately and sensibly."
French border officials
Last weekend, Port of Dover chief executive Doug Bannister said there had been inadequate staffing from French border police.
Georges-Francois Leclerc, the top official for the Hauts-de-France region, which covers Calais, did acknowledge that some staff were delayed getting to their Dover booths due to technical issues, but only by 75 minutes.
Ahead of this weekend, Mr Bannister said there was a "significant dialogue" with the government and French officials to ensure the required resources are in place.
Both of the Conservative leadership candidates have put the blame on the French authorities.
- Rishi Sunak said: "They need to stop blaming Brexit and start getting the staff required to match demand"
- Liz Truss said: "The French authorities have not put enough people on the border"
Ahead of Brexit, the government was warned there could be queues at times after the transition period ended on 31 December 2020.
The National Audit Office pointed out: "The government modelled some scenarios, which showed that queues at Dover and Eurotunnel could be one to two hours in January 2021 but become much longer in the summer months, especially at Dover."
This level of queuing did not materialise last year as Covid restrictions led to reduced travel.
But now that passenger volumes are back to normal, the effect is being felt. Mr Bannister has said that Dover planned for the impact of longer checks and communicated with the French authorities over increased staffing levels.
However, Pierre-Henri Dumont, the MP for Calais, claimed in a tweet that there had been a lack of investment in checkpoints by the UK government.
In December 2020, the Financial Times reported that the UK government had turned down a £33m plan for more French passport booths at Dover - a doubling of the total from five to 10.
The Guardian quoted an official from the Department for Transport saying the department "did not comment on individual bids".
Mr Bannister said extra money needed to be spent on the British side.
"We do require greater investment in the port and greater investment throughout Kent to manage traffic."
Last week ITV news reported that the Port of Dover was working with French authorities to increase booth capacity by 50%.
Less capacity on the roads
The M20, one of the main roads down to Dover, has been partially shut to act as a giant lorry park for freight vehicles awaiting checks before travelling to France.
Last Friday, there was a serious crash on the motorway that further reduced the number of lanes.
Toby Howe, Senior Highways Manager at Kent County Council, and tactical lead at the Kent Resilience Forum told the Today programme: "It is a very vulnerable situation. It takes very little to cause further issues."
He said that France was able to deal with delays better as they have much more space at Calais and added "really we shouldn't have to be using our roads as lorry and car parks".
How long could these delays continue?
There could be worse disruption in the future.
In November 2023 the EU's new Entry Exit System will come into place. It will see travellers facing biometric checks before travelling to France.
The authorities at Dover fear that if the checks require travellers to get out of vehicles there could be serious disruption and delays at the port.
The European Travel Information and Authorisation System (Etias) visa waiver system will come into force at the same time, meaning British passport holders will have to fill in relevant forms, pay a fee and be approved before travelling to the EU.