PRINCE Charles and the Duchess of Cornwall are expected to be in Simonsbath on Wednesday to attend the National Parks Big Picnic.

It is already fully-booked – the 500 tickets were allocated within less than two weeks.

It is being held to mark 70 years since the 1949 National Parks and Access to the Countryside Act that gave rise to UK National Parks was passed.

The royal couple will be joined by Niall Hobhouse, grandson of Arthur Hobhouse who led the 1949 Act.

Following decades of campaigning, the Act provided the framework not only for the creation of national parks but also for Areas of Outstanding Natural Beauty and addressed public rights of way and access to open land.

Seventy years on, the UK has 15 national parks, each with its own distinctive character and collectively worth almost £6 billion to the UK tourism economy.

Those at Wednesday’s Big Picnic, will gather in Simonsbath’s riverside meadows, at the heart of the former Royal Forest, where some of the area’s produce, crafts, culture, history and local breeds will be showcased.

A new film on the history of UK national parks, presented by Campaign for National Parks president Caroline Quentin, will be previewed at the event ahead of a major exhibition in Northumberland national park’s ‘The Sill’ later this year.

Sarah Bryan, Exmoor National Park Authority chief executive, said: “We’re thrilled to be welcoming Their Royal Highnesses to Exmoor and deeply honoured to be hosting this celebration.

“National parks offer so much to the country and simply wouldn’t exist were it not for the foresight and determination of those who fought for their establishment.

“We have been amazed and encouraged at the strong demand for tickets from those wishing to help mark this special occasion. We regret anyone without a ticket will be unable to join us due to the limited capacity of the site.”

The Exmoor Society and the Exmoor Hill Farming Network (EHFN) helped organise the Big Picnic, and the chairmen of both said they were honoured to host the royal couple.