Members of the Flemish nationalist group at a demonstration in 2007 Getty

After every act of terror that shakes the world, it seems as though the far-right cranks and extremists come crawling out of the woodwork. The story is no different following the atrocity in Brussels, which claimed the lives of 31 people and injured more than 300. The Belgian far-right has come out fighting in the wake of the attack, with ultranationalist group Voorpost leading the charge.

Its leader Bart Vanpachtenbeke has claimed to Mail Online that the group's membership has leaped up since the bombings in Belgium's capital. "A huge number of people have started supporting us online. We have had more than double the number of new members in the last three days," he said.

Voorpost, which means "outpost" in Dutch, has a long history of inciting anti-Muslim hatred, but it is above all a Flemish nationalist organisation. This means its members want nothing more than to reunite Flanders, the Dutch-speaking parts of Belgium, with the Netherlands, Afrikaner South Africa and even French Flanders, Dutch-speaking areas of Germany and Suriname, to "restore" a largely mythical polity that would be known as the Greater Netherlands.

Alongside Flemish nationalism, though, Voorpost is avowedly against immigration, multiculturalism, and Islam. It has branches in Holland, Flanders and South Africa, and regularly holds marches and demonstrations in which its followers wear a blue uniform and brandish the Flemish flag – a rampant black lion on a yellow background. The group is also anti-EU, anti-Belgian and, oddly, pro-ecological.

Founded in 1976 by a member of Vlaams Blok, a now-banned far-right Flemish political party, Voorpost maintains links with other European nationalist organisations. One 2014 action saw the group remove flags celebrating 50 years of Turkish integration in the Belgian city of Ninove and replace them with their own.

"There is anger in Brussels now," Vanpachtenbeke, who is rarely photographed without wearing a natty bow-tie, told the Mail. "I think there are dark times coming. We can't give any information, but we are planning a lot of new protests. There is a lot of drastic action, a lot of noise coming."

Voorpost's social media is draped in the usual race-baiting memes and anti-immigrant rhetoric, and features plenty of pictures of angry white men waving flags wearing military fatigues. They don't seem to have the online power of other groups like Britain First or Pegida, though; their Twitter account doesn't quite have 800 followers, while they have a few more than 1,750 likes on Facebook.