Overbearing health and safety regulations are hampering the ability of the National Trust to encourage more people to venture outdoors for walking or to visit country houses.

The charge is made today by Sir Simon Jenkins, the new chairman of the trust, who claims that the rules are obstructing his efforts to offer visitors an insight into what it would be like to live in some of its properties.

In an interview with The Times, he calls for a new offensive to challenge the climate of risk aversion in Britain. He has also ordered the trust to shake off its “elitist” image and for the houses to be less “samey”.

Conservators have been instructed to act more like impresarios than curators in changes intended to attract new visitors through the doors of their properties. Sir Simon also hopes that his tenure at the trust, whose patron is the Prince of Wales, would be an opportunity to “make peace” with modern architecture.

“The trust is so emphatically of the Prince’s persuasion and I’ve always gone along with his general line, but I think it would be nice to employ modern architects to do extensions to buildings, as we’ve used modern sculptors in some gardens. It would answer the charge that we are old-fashioned, not that we are.”

The new chairman is clearly laying a claim for the trust to become a more prominent force in the nation and to blow out some of the cobwebs that have enveloped the nooks and crannies of the organisation.

Sir Simon made clear that he was ready to speak out over controversial developments, such as the expansions of Heathrow and Stansted, and any other threat to the countryside.

On health and safety, he was emphatic. “We must loosen up our houses and properties. Saving these houses for posterity is our priority obligation, but in presenting these houses to the public I want people to be able to look out of windows, go on terraces and peer through battlements. We have to take more risks.

“But you find every argument is under the control of regulatory compliance. It goes from someone trying to decide if the public can be allowed on the terraces of Penrhyn Castle or whether the manager of an adventure centre in the Lake District has to fill in a risk assesment for each party of schoolchildren.

“This is a plague and it is not just something that affects the National Trust. It is something I would join as a campaign to see if we can’t get some protocol of reasonableness from health and safety authorities to free people from total risk aversion.”

He added: “Overzealous health and safety regulations are impeding more public participation in our properties. I do think my staff feel they are in an excessively bureaucratic straitjacket on matters of statutory compliance.”

His words are intended to open a debate on the subject and to encourage the views from other voluntary organisations involved in public participation and activity.

A recent visit to the Cambrian Mountains persuaded him of the need to raise the issue. “I was on Cader Idris the other day and fell into conversation with a school party. The boys could not swim in the lake – and these boys were the rugby club. They could not go more than 100 yards ahead of the teacher. It wasn’t like that when I was a boy, and it is clearly a disincentive to enjoy the outdoors. We have thousands of kids who use National Trust properties and I know talking to staff they feel oppressed by the bureaucracy of compliance.”

Sir Simon, a former Editor of The Times, is convinced that the burdensome controls are stifling interest in exploring the countryside and that fear of trips, slips and hazards is preventing his mission to open up trust properties for new activities. His concerns were relayed to trust managers this week. He has asked them to take on more risks, make their properties more individual and encourage greater use by local people.

He wants to see a step change from present practice. “I do think we could be living in more property than we do. I hate a dining room where no one eats, a kitchen where no one cooks and a ballroom where no one dances. The trust has been inclined to conserve houses as museums, and I understand there was a need to ensure works of great British architecture were saved. The next stage is how to make visitors feel they are visiting an occupied property.”

He would like to see a host in every house and, ideally, that person would be somone from the family that built or handed over a property.

“The great thing at Chatsworth is that the Duke [of Devonshire] lives there and the Duchess wanders around with the visitors. I have joked that I will leave in my will enough money to cover the cost of a labrador and a child’s pushchair to put in the front of every National Trust house to make it look lived in.”

Times recommends

• Energy-saving ideas from switched-on professor
• Rooks are as clever with tools as chimpanzees
• Burping of the lambs blows roast off menu