Ramblers have warned that proposals to change how walking trails are managed will pose an enormous risk to the quality of the routes.
Ramblers, a charity which promotes countryside walking, said its main concern was a lack of a “national champion” to oversee the 13 trails as a whole, including the South Downs Way.
The consultation paper by Natural England suggests that management of the trails should be devolved to councils and voluntary groups along with a change to the way they are funded.
Rhiannon Wadeson, Ramblers senior campaigner, said: “By fragmenting responsibility and handing over funds to cash-strapped local authorities, who are already struggling to maintain local footpaths, the government puts at risk an important part of our national heritage.”
The charity says that the 12 million annual users of the trails produce huge amounts for local economies.
The charity hopes that the backing of celebrities such as BBC radio presenter Stuart Maconie and journalist Janet Street-Porter will help its voice to be heard.
Ms Street-Porter, who is also the vice-president of Ramblers, said: “Our national trails provide some of the best walking opportunities in this country; under no circumstances should they be compromised.”
While Ramblers has reservations about the proposals, the South Downs Way may not be so vulnerable, according to The Argus walking trail columnist Ben Perkins.
Mr Perkins, journalist and South Downs Society member, said: “The Ramblers charity is quite right to be anxious about certain trails around the country.
“Fortunately for the South Downs Way, we are better prepared than most because the creation of the South Downs National Park last year allows a more joined-up approach to management.”
The consultation paper on the issue has recently closed.
A Natural England spokesman said: “We welcome the Ramblers’ comments, which will be considered alongside the other 130-plus responses we have received to the consultation.
“Natural England is committed to ensuring that national trails should be as good as, if not better than, they are today.”