People looking to leave the country via The Channel are being met with a third day of travel chaos, but what exactly is the problem?

Some travellers, including children and staff on school trips, have been left waiting for up to 19 hours at the Port of Dover.

Problems in Dover started on Friday, with many people left in their vehicles without food or drink as they waited to board their ferries.

It's left many asking what the problem is and if it was preventable.

The short answer for the reason behind the chaos: Brexit.

Travel expert Simon Calder said "for decades" we have had juxtaposed border controls at Dover", meaning we had French officials checking our passports at the Kent site before we boarded the ferries.

"Normally that's great, because it means when we get to Calais it means off you go, you're free to go," he explained to Sky News.

He carried on, saying after the UK signed up for Brexit that the Port of Dover became a "hard external EU frontier" similar to what they have in Russia and Turkey.

Previously, travellers would turn up in their cars and show their passports before being waved through by officials.

Now, those same officials are required to go through the passport, check all the stamps before stamping it and replicating that process for every person – which has led to particular problems for coaches.

Mr Calder added: "That, on occasions, is being replicated 50 or 60 times. And however many French officials you can send over, it's simply going to back up."

He went on to suggest some travel capacity restrictions, similar to what is happening at Eurostar, could be introduced.

Port bosses said the queues had been caused by a number of factors, including the "lengthy immigration process" and "sheer volume of traffic".

A statement from the Port of Dover said: "The port has been working round the clock with the ferry operators and border agencies to get coach passengers on their way, with extra sailings being put on overnight to help clear the backlog.

"More than 300 coaches departed the port on Saturday, with all of the freight backlog cleared and tourist cars processed successfully.

"There remain pockets of coaches still waiting to be processed with smaller volumes of coaches expected today.

"The port remains deeply frustrated by the continuing situation caused by a mix of lengthy immigration processes at the border and sheer volume of traffic, particularly on behalf of those who have waited for such a long time.

"Minimal freight is expected today and so the focus remains on ensuring all partners work to get the remaining coaches and other tourist traffic on its way as soon as possible.

"We continue to offer our sincere apologies for the prolonged delays."

However, Home Secretary Suella Braverman says it isn't "fair" to put the blame on Brexit.

She said: "We've had many years now since leaving the European Union and on the whole there has been very good operations and processes at the border.

"But what I would say is that at acute times, when there is a lot of pressure, crossing The Channel, whether that's on the tunnel or ferries, then I always think there is going to be a backlog.

"And I urge everybody to be a bit patient while the ferry companies work their way through the backlog."

This morning, the Port said it hoped to clear the backlog by lunchtime and issued an update saying border processing times for coaches remained three to four hours.

At 6.30am, P&O Ferries warned its passengers the wait was five to six hours.

It tweeted: "We apologise for the wait times in Dover this morning. The current wait at the entrance to the Port of Dover is approximately 5-6 hours.

"Once coaches reach our check in desks they will be on the next crossing to Calais."

Dover MP Natalie Elphicke (Con) was quick to point the finger at the French.

She said: "Incredibly disappointing to see French border control problems once again adding to traffic mayhem just as families are trying to getaway for the Easter holidays."