It has always been known for its loving care of some of the greatest estates and now its not just gardens that the National Trust wants to keep green.

One of the country's most-loved charities has given its staff Leap Year day off and asked them to use the time to make their own homes environmentally friendly.

The organisation, which looks after heritage sites like great estates, castles, famous gardens and nature reserves, wants its workers to use February 29 to reduce their domestic carbon footprint.

"This is an extra day in the year which employers usually take from their staff - why don't we give it back to staff to use it in a positive way to do some practical things at home," said the Trust's Director General, Dame Fiona Richards.

"Individual actions can make a difference," she told Reuters. "If only a million people changed one light bulb and turned their thermostat down one degree it would save over 350,000 tonnes of carbon."

The organisation's 4,800 staff and 5,000 volunteers are being encouraged to do things like install energy-saving light bulbs, insulate roofs or get a composter.

The National Trust said it hopes employers of the country's 29 million workers will follow their lead.

"It's a reminder that small actions done by a lot of people can add up to make a real difference," said Richards.

The Trades Union Congress backs the plan and told Reuters it is urging the government to create a new Community Day public holiday.