Brits are at risk of being turned away from the airport due to a "fundamental misunderstanding" this summer. Tourists heading to Scandinavia could be rejected by airlines at the gate if they are using an older passport.

As reported by The Guardian, it has emerged that some people could be denied boarding flights due to the "inconsistent" application of Schengen travel rules. One traveller, who was due to fly from Gatwick to Copenhagen, was recently turned away by the airline Norwegian because her passport was issued "more than nine years and nine months ago".

Denmark follows Schengen area rules, which means a passport must be within 10 years of its issue date on the day you enter. It must also be valid for at least three months after the end of your trip.

However, the traveller who was turned away from the airport held a passport that satisfied both criteria. She was denied boarding on March 23 with a passport with a date of issue of June 13, 2015 and an expiry date in August.

She said: "Upon arriving at check-in, the automated system directed me to the desk. The staff member consulted a colleague, who stated my passport was invalid because it was issued more than nine years and nine months ago.

"But there is no such rule. This decision demonstrates a fundamental misunderstanding of the actual entry requirements."

She added: "I attempted to explain this to the staff, including the manager, but was dismissively told that ‘others have complained on social media’ and that there was ‘no way’ I would be allowed into Denmark."

The Copenhagen police department, which is responsible for border control at the airport, said once a passport was nine years and nine months old it was invalid. The force added that Schengen did not recognise extensions of 10-year passports.

A Norwegian employee at Gatwick Airport recently said the airline was turning away "six people a day" due to the rule. A British tourist was also reportedly deported from Norway in February, according to the Independent.

The woman who was turned away from her flight has lodged a formal complaint with Norwegian. The fiasco cost her hundreds of pounds on an emergency passport renewal and replacement flight.

She was due to attend the Copenhagen international documentary festival, explaining: "This was a significant opportunity for me to present and pitch my films. As a result, I missed two full days of the festival and incurred personal losses of about £700."

Although Norwegian could not comment on the individual case, it said: "We regret the disruption to our passengers due to inconsistent interpretation of Schengen passport rules by the Nordic countries.

"As an airline, we must comply with local border control directives which are currently unclear. We have urged the authorities to provide clear, unified guidance to airlines, in order to prevent further passenger issues and avoid penalties for our company."