Counterterrorism authorities are uploading a film on Youtube today to tell holidaymakers what to do if they are caught up in an attack.

Travel industry staff are also being briefed on the initiative.

Police and government ministers are supporting the effort and encouraging travellers to take note of the “run, hide, tell” safety procedure.

The four-minute film has been produced to help to explain the message and depicts a gun attack at a hotel and the action that guests should take.

More than 20,000 travel representatives have been trained in safety measures including how to spot suspicious items and activity, as well as what to do in the event of a major terrorist incident.

Abta director of destinations and sustainability, Nikki White, said: “We know that customers would look to those staff working in their hotels and resorts to take the lead and respond quickly to an emerging situation.”

Thirty 30 British holidaymakers were among 38 people killed when a gunman opened fire at a Tunisian beach resort two years ago.

The police said that there was no specific intelligence that Britons were being targeted this summer but they hoped that people would treat the message in the same way they would safety precautions on an aircraft.

Detective chief superintendent Scott Wilson, national coordinator for the protect and prepare strategy, told The Times: “As we saw in Tunisia in 2015 any westerner is likely to be a target anywhere in the world. That’s the sad reality of it. The chances of it happening are still very low.

“We’ve seen attacks in numerous countries so we are trying to say western tourists overseas should be aware of what they should and shouldn’t do if they are caught up in such an attack.”

The “run, hide, tell” message was introduced by the police in December 2015 and was put into use during the London Bridge atrocity last month in which eight people were killed and 48 others injured.

The guidance says that people should run to a place of safety if there is a safe route, leaving belongings behind and insisting that others go with them.

If there is nowhere to go then they should hide by barricading themselves in a room and turn their phones to silent.

Then, only when it is safe to do so, they should attempt to alert the authorities by calling the local emergency number, which holidaymakers should find out in advance. For EU countries it is 112.

Wilson said: “The chances of being caught up in a terrorist incident are still low but sadly we have seen atrocities take place in the UK and abroad. So it is important everyone stays alert and knows what to do if the worst was to happen.

“We want people to think of this in the same way they do the safety film airlines show before take-off. They don’t expect anything bad to happen but it is a sensible safety precaution to show people what to do.”

Foreign office minister Lord Ahmad encouraged people to watch the film before they go away.

“While there is no specific information that British holidaymakers will be targeted this summer, it sets out some simple steps we can all take to minimise the impact of an attack if one does take place,” he said.