The National Trust urgently needs to recruit more young volunteers after research revealed that only 4 per cent are under 35.
A total of 2,000 volunteers at 280 National Trust properties were questioned for Vital Volunteers: Celebrating the Benefits of Volunteering, making it the most detailed snapshot yet of the charity's volunteer workforce.
The survey shows that the trust faces a shortfall in volunteers because just over half are over 65. Almost two-thirds of its sites already need more volunteers.
The charity has responded by drawing up a strategy that aims to make it easier and more rewarding for people to become stewards or guides at its homes and gardens.
The trust will try to attract more young people by running 'taster days' at its sites and by providing transport.
It has also identified that training is a strong incentive to younger volunteers, with 61 per cent saying that it was the opportunity to learn new skills that first attracted them. So the trust plans to develop new training approaches and accreditation for volunteer stewards, customer service reps and guides.
Fiona Reynolds, director-general of the trust, said: "The issue of how to bring in younger audiences remains a challenge. The trust is so reliant on volunteering support that the issue of extending our volunteering base is fundamental. No volunteers means no National Trust."
But the research also made some positive findings, such as the fact that 25 per cent have volunteered with the trust for more than 10 years.