In a speech at easyJet’s headquarters in Luton, Cameron highlighted research from the Treasury that suggested Brexit would cause the pound’s value to drop by 12% against major currencies such as the euro and US dollar.

The Treasury has calculated that an eight-night holiday for four people to a EU country would cost an extra £230 on average, while the cost of a 14-night trip to the US for four people could rise by £620.

The report argued that costs such as accommodation, and food and drink would be “higher for families travelling overseas”.

Cameron said: “All the evidence points to the value of the pound falling after a vote to leave the EU. A weaker pound means people’s hard-earned savings won’t go as far on holidays overseas.

“The choice facing the British people on June 23 is increasingly clear: the certainty and economic security of remaining in the EU, or a leap in the dark that would raise prices – including the cost of a family holiday.”

Cameron made his speech in front of easyJet staff today and the airline’s chief executive Carolyn McCall also supported his views.

She added: “If the UK were to vote to leave the EU any new, more restrictive aviation arrangements would add cost and therefore fares would rise. And a weaker pound would mean the cost of a holiday abroad – including food, accommodation and drinks – would be more expensive.”

Vote Leave’s chief executive Matthew Elliott accused Cameron of “talking down our country and our economy day after day”.

“These threats lack credibility - the pound has actually been stable in recent months as the possibility of Brexit has increased,” he added.