The farmers’ party BBB is on course to become the biggest group in the new senate with 15 seats, according to an exit poll for national broadcaster NOS.

The left-wing parties GroenLinks and Labour (PvdA), who will form a joint faction in the upper house, are also projected to win 15 seats, with eight for Jesse Klaver’s GroenLinks and seven for the PvdA.

The four parties in Mark Rutte’s cabinet lost eight seats altogether, going from 32 seats to 24, with Rutte’s VVD winning 10. But if the poll is borne out in the result, the government could secure a majority in the senate with the support of the left-wing duo.

Caroline van der Plas, leader of the BBB, said it would be a ‘scandal’ if her party was shut out in the senate after taking a projected 19% of the vote.

‘They’d be ignoring a large proportion of voters in the Netherlands. They haven’t taken the people seriously in recent years. Now is the time to take people seriously. I’m open to talks with everybody and we are ready to take part.’

Among the losers are set to be the Christian Democrats (CDA), who look to have haemorrhaged votes to the BBB and would lose five of their nine senate seats.

D66 and the ChristenUnie, the other two coalition partners, would each lose one seat.

Two new parties are set to enter the senate – the pro-European party Volt, with two seats, and the hard-right JA21, who are projected to win three.

The biggest losers are Thierry Baudet’s Forum voor Democratie, who would retain just two of the 12 seats they won after the last provincial elections in 2017. Forum’s share of the vote dropped from 14.8% to 3% after four years in which the party was riven by in-fighting and defections.