"Perhaps it was health and safety, but what could you do with a ride-on mower?"
The issue was raised by Daily Telegraph reader Mark Solon, who wrote to the paper saying: "My gardener with over 50 years' experience has been told by the National Trust he can no longer cut their grass as he doesn't have the right qualifications. Perhaps he should have taken a degree."
Mr Solon added: "Experience is more important than a certificate. My gardener has a profound knowledge of the land gained over 50 years. He can mow a lawn without further study. The National Trust has lost an exceptional practitioner."
A spokesman for the Trust said: "The National Trust has owned Shute Barton since the 1950s and until 2009 it was leased back to the historic family, who employed their own gardener. Since 2009, after the family decided to give up their right to live in the property, the Trust has managed Shute Barton directly.
"When the Trust took the property on it needed extensive renovations before becoming a holiday cottage in 2010. The Trust decided to use its own garden contractors and gardeners to look after the grounds as the management needs of the garden are different to when it was a family home".
Many of the jobs advertised on the National Trust website require gardeners to have formal qualifications such as health and safety certificates or an RHS horticultural qualification.
Some roles, including one as an Assistant Gardener at Belton House, in Grantham, Lincolnshire, which pays £15,891 a year, require applicants to have an NVQ 1-2 in Amenity Horticulture.
The Trust said it also has multiple programmes which do not require qualifications including paid apprenticeships and an in-house staff training scheme known as the Heritage Gardening Programme.
The spokesman added: "As with many jobs, different roles require different levels of skill and experience, shown on application by appropriate qualifications or equivalent levels of vocational experience.
"Some roles may also require practical certificates, for example in the use of machinery or equipment. This will be dependent on the requirements of specific properties."
-The Daily Telegraph