A television series, a book on the salvation of Britain's heritage and a series of projects including the opening of the long-awaited new spaces at Stonehenge will turn the centenary of a government pledge to protect historic landmarks into a memorable year of reflection.

English Heritage, the modern-day guardians of sites ranging from war bunkers to Hadrian’s Wall, will reopen Kenwood House, Robert Adam’s revered 18th century Hampstead Heath home of some of one of the finest art collections in the country, as part of the plans.

Further south, Stonehenge’s much-heralded new facilities have been at the centre of a convoluted enhancement project, and the new galleries and visitor attractions are part of a wider effort to restore Wiltshire’s druidic heartland.

History enthusiasts should keep an eye on BBC Four. Heritage! The Battle for Britain’s Past will follow the campaign to safeguard domestic heritage, initiated by the Ancient Monuments Act of 1913 under Herbert Asquith’s government.

Dr Simon Thurley, the Chief Executive of English Heritage, is the author of The Men from the Ministry: How Britain Saved its Heritage, a book explaining the heritage role played by the state.

“Imagine England without Stonehenge, its great castles and abbeys and its historic monuments,” he said.

“It is largely thanks to the Act that these stone, brick and iron eye-witnesses to our past survive today to tell their story.”

Thurley’s precise motivations differ from his earliest predecessors. The Act was created to dissuade American collectors, keen on buying historic houses and interiors before transporting them across the Atlantic.

Lord Curson, the former Viceroy of India with a Taj Mahal restoration to his named, warned that the government was left “absolutely helpless” to stop the removal of panelled rooms, staircases, fireplaces, ceilings and other assets from important houses.

“We regard the national monuments to which this Bill refers as part of the heritage and history of the nation...they are documents just as valuable in reading the record of the past as any manuscript or parchment deed.”

Envisaged as a national outdoor museum, the Act also established the National Heritage Collection, which looks after 880 historic sites under the care of English Heritage, Historic Scotland and CADW in Wales.

Other dates during the centenary – launched at London’s Lloyd’s Building, the 1980s development which is the youngest to have gained Grade I listing status – include exhibitions at the capital’s Wellington Arch, public openings of unseen apartments at Warwickshire’s Kenilworth Castle and a survey of public libraries, post-war art and signal boxes.

• Visit the campaign online for full details, and follow English Heritage on Twitter @englishheritage.

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