Amid the dog-eared form guides, jaunty head wear and crumpled betting slips, racegoers attending Royal Ascot next week may notice an altogether different addition - breathalysers at the turnstiles.

The Berkshire venue has rolled out a swathe of measures across all enclosures and general areas designed to curb some of the overzealous behaviour which has blighted race days across the country in recent months, ahead of the start of Ascot's five-day meeting on Tuesday.

These include the introduction of specialist trained incident "spotters" to identify potential trouble before it takes hold, and drugs amnesty boxes outside the racecourse, while mobile beer sellers have been discontinued.

Following a successful trial in May, more than 20 specially trained drugs dogs will be used to identify people in possession of illegal drugs, patrolling key areas across the site including entry points outside the course, public bars and queues for the toilets and car parks.

Those found in possession of illegal drugs on entry or on site will be refused entry or expelled.

The event will also see breath tests for customers on entry who are showing what Ascot organisers described as "overt signs of inebriation".

Those who are deemed to be drunk will be refused entry.

Racecourse bosses have been forced to act following unsavoury scenes at recent meetings across the country, where alcohol-induced scraps which left punters' finery in tatters have been caught on camera phones and shared widely on social media.

Guy Henderson, Ascot racecourse chief executive, said: "Every year as part of our preparations for Royal Ascot we review our security measures alongside our expert partners.

"We want all guests to feel comforted and reassured and we believe that the combination of armed police, patrol dogs and high-level security will provide this.

"The use of illegal drugs and their contribution to anti-social behaviour is a significant issue for all major events.

"This year we will continue proactively to address these challenges with an increased specialist security team, supported by more visible stewarding around bars and other areas in order to pre-empt incidents arising from excess alcohol consumption or other anti-social behaviour.

"As has always been our policy anyone found entering or on the site with illegal drugs will be refused entry or expelled.

"We are looking forward to a tremendous five days of racing and to welcoming some 300,000 people to this very special celebration of our sport, British culture and fashion."