Tourists have been reporting lengthy delays at airports across Europe following the official introduction of new digital border controls on 10 April.

The new Entry/Exit system, known as EES, is being implemented across 29 countries but early reports indicate that many countries are experiencing problems with the biometric border control process.

The much-delayed EES is a digital system that replaces traditional passport stamping when entering or leaving the Schengen area. It records a traveller's photo, fingerprints and passport details each time they cross a border.

Visitors may also be questioned about the reason for their visit.

"There is a complete disconnect that EES is working well, and the reality, which is that non-EU travellers are experiencing massive delays and inconvenience," IATA said in a statement.

"We need to be realistic about what will happen during the peak summer months, when traffic at Europe's airports doubles.”

Europe is also rolling out a separate border security measure at the end of the year. The European Travel Information and Authorization System (ETIAS), will require travellers from visa-exempt countries to apply for authorisation before departure.

Who will use the EES

Most non-EU citizens travelling for short stays of up to 90 days in a 180-day period will use the EES. Children under 12 years old only need a facial scan.

How much does an EES cost?

Nothing. It's free.