By Anna Hol

A farmers' party has stunned Dutch politics, and is set to be the biggest party in the upper house of parliament after provincial elections.

The Farmer-citizen movement (BBB) was only set up in 2019 in the wake of widespread farmers' protests.

But with most votes counted they are due to win 15 of the Senate's seats with almost 20% of the vote.

"This isn't normal, but actually it is! It's all normal citizens who voted," said leader Caroline van der Plas

The BBB aims to fight government plans to slash nitrogen emissions harmful to biodiversity by dramatically reducing livestock numbers and buying out thousands of farms.

But its appeal has spread rapidly beyond its rural heartland, on a populist platform that represents traditional, conservative Dutch social and moral values.

Shocked by the scale of their success, Ms van der Plas told supporters that voters normally stayed at home if they lost faith in politics: "But today people have shown they can't stay at home any longer. We won't be ignored any more."

A left-wing Green-Labour alliance is also on course to win 15 Senate seats, while Prime Minister Mark Rutte's four-party coalition is poised to fall back to 24 - down eight seats.

Turnout in Wednesday's vote, estimated at 57.5%, was the highest for years and the biggest loser of the night was the far-right Forum for Democracy party.

For rural voters, the main incentive for backing the BBB was to protest against cuts in nitrogen emissions, according to an Ipsos poll for public broadcaster NOS.

But voters also turned out in force for the Greens, and environmental groups warned that the Netherlands' problems were not going away.