A new high-speed rail service linking Bordeaux with Spain threatens to destroy prestigious vineyards, wine unions have warned.

Ten wineries in AOC Graves will see 40-50ha of their land destroyed by the rail route, which also passes through Toulouse and which French authorities approved this week.

Local wine union Syndicat Viticole des Graves (SGV) denounced "the sham of a consultation process" on the route.

"The oldest Bordeaux vineyard is threatened not only in terms of the quality of its terroir but also with regard to the impact on the countryside," it said.

"We are more determined than ever to pursue our campaign against this project."

The new rail route will potentially affect renowned châteaux such as Le Tuquet, Méjean, Saint-Jérôme, Grand Bos, Haut Selve and Castres.