Those driving to the Continent are being advised to leave extra time for their journeys when new exit checks come into force next month.
Immigration minister James Brokenshire has admitted the checks, which will see security officers checking every passport for the first time in 20 years, might lead to delays at busy times.
In an interview on BBC Radio Four’s Today programme, he said: “On busy days, I think it’s advisable for anyone to set out earlier to ensure that they’re at their port of departure on time.”
The new border checks, which come into force on April 8, could hit families hardest as it will take twice as long for a car with four passengers to pass through security.
And ferry companies are already warning the new checks could create queues more than 650 vehicles long, which raises concerns that they might block major roads.
Mr Brokenshire said the government had been working with ferry companies and Eurotunnel for the last 18 months and said he was confident the process would be effective.
