British travellers were reportedly among those prevented from boarding flights to the US yesterday after the US Customs and Border Protection visa website crashed following an “update”.

The online service stopped working on Saturday after an upgrade intended to “modernise” the site, The Times reported.

It meant that travellers from the 39 member countries of the Esta visa waiver scheme who had not applied for the document before Saturday were turned away from their flights.

The website enables travellers to apply for Electronic System for Travel Authorisation (Esta) and pre-screens them before they board an aircraft or ship. The permit allows them to visit the US without a visa for up to 90 days.

Social media was inundated with people complaining about the crash and questioned why the website was updated at the weekend, when no one could be reached for assistance, according to the newspaper.

Jess Lipson, a computer designer from London, had to cancel a Virgin Atlantic flight to Los Angeles for a week-long visit to a friend for Thanksgiving.

She told The Times: “I was due to see my best friend, had taken time off work and arranged for the children to stay with the grandparents so it is very upsetting. I’ve also had to pay £150 to change the flight to February and cancel a $300 hotel.

“It’s partly my fault as I should have applied for the Esta earlier but I’ve never been to the US before and didn’t actually realise I needed to have one.

“I work with computer programmers and the number one rule is never roll out an update on the weekend, especially without properly testing it.”

Belfast software engineer William Park was stopped with his girlfriend at Dublin airport en route to Philadelphia and Las Vegas.

He said: “So far this has cost me €80 for another hotel stay in Dublin and the expenses for the guaranteed seating on the outbound flights. If the new Esta doesn’t come through it will have cost me over £1,500 for the holiday itself and tours I had booked that I can’t enjoy.”

A spokesman for US Customs and Border Protection (CBP) said that people who experienced problems may be able to claim compensation.

But he added: “CBP has for many years recommended that prospective travellers complete the online Esta form at least 72 hours in advance of travel to ensure sufficient time for processing.”