The National Trust has opened its doors to the nation’s best-loved cartoon characters this summer letting The Beano’s mischief-makers run riot across the country.

Billy Whizz has been let loose on Lyme Park in this week’s issue of The Beano and it is the first ever time the National Trust has given fictional characters keys to all of its 300 homes and access to the 617,500 acres of land it cares for.

The Beano team of illustrators and comic whizzes have had full creative control as characters from Dennis the Menace to Billy Whizz conquer castles and race ponies across grand estates.

The Beano characters have invaded to help the National Trust bring its places to life and prove that its doors (and copious amounts of fresh air) are open to all – breaking down preconceptions of the organisation.

Billy Whizz has a fast-paced day topped off by a good night’s sleep in Lyme Park’s Edwardian Nursery. Georgina Ferguson, visitor experience manager at Lyme Park says: “We’ve got a great Billy Whiz quiz around the house – you’ll be exhausted doing it!

"For younger visitors there’s a Beano comic strip to colour in and we’re also giving away copies of the Beano magazine to everyone who completes our visitor survey – so get your skates on and – just like Billy – whiz over to Lyme Park”.

Meanwhile, Billy Whizz’s mates, Dennis the Menace and Gnasher kick off the chaos as they conquer Powis Castle in Wales, fooling National Trust staff with dozens of “hedge menaces” disguising the real rascal and his companion and becoming King for the day.

The Numskulls, who live inside Edd’s nostrils (of course), are sneezed out at Edwardian Surrey estate Polesden Lacey into a game of croquet – and a planned bug hunt – to enjoy the buzz of bumblebee racing.

While Minnie The Minx takes her dad on a manic trip to Northern Ireland to discover the iconic Giant’s Causeway – and find the giant Finn McCool himself.

The Bash Street Kids take over Devon family manor Arlington Court as they enjoy the great outdoors – bat watching and pony racing with a less than happy teacher to calm them down.

Fellow mischief-maker Billy Whizz – the fastest boy in The Beano – explores the country in less than a day. Fooled by Attingham Park’s false doors, to completing Cragside’s 8 foot high rhododendron maze in seconds and experiencing life as an Anglo Saxon at Sutton Hoo in Suffolk, Tony Berry, visitor experience director of the National Trust, said: “We are delighted to open our doors to The Beano and all of its mischievous characters.

"The National Trust and The Beano are both British institutions and we are hoping the news that we have opened our doors to them all will encourage families to take a leaf out of Dennis’ book and organise a trip to one of our places.

"As our black and red stripy friend says; ‘a menace always has a plan’ and this summer should be no exception.

"Wherever we can we have tried to take away ropes and show the fun side of our places with everything from mazes to talking portraits. We are certain that real-life Dennises will find that it is not all ‘please don’t touch’ anymore – in some places you can even have a go on the snooker table.”

John-Paul Murphy, from The Beano publishers, D.C. Thomson, said: "We couldn’t think of a better way to prove what fun kids can have at ‘Gnashional Trust’ properties by letting the world’s most famous menace and his friends from Beanotown loose on them.

"Dennis hasn’t let his own 60th anniversary affect his ability to cause his own brand of havoc and it is a fitting birthday treat for him to become ‘King of the Castle’ at Powis.

"We’re sure Beano readers will have just as much fun as the characters have when they visit the venues featured in our comic this summer.”

The Gnashional Trust issue of The Beano went on sale this week. For a behind-the-scenes look at the takeover visit www.nationaltrust.org.uk/thebeano Lyme Park Hall is open Fri – Tues, 11am – 5pm (between 11am and 12noon entrance to house is by guided tour only).

The garden and park is open daily. Go to www.nationaltrust.org.uk/lymepark for further details.