Never drink in a pub with a flat roof, or so the joke goes back in the UK.

It refers to the type of dismal drinking establishments that sprang up on post-war housing estates, where you might encounter all sorts of dodgy characters, addicts and psychos. The same goes in the Czech Republic, too – you might run into a nutter like Vandam (Hynek Čermák) in Štěpán Altrichter’s National Street.

Vandam is the resident hard man of the drab Severka pub in a southern Prague project. They call him Vandam because he can do 200 push-ups, just like his VHS hero, Jean-Claude Van Damme. With his skinhead, stocky build and menacing brow, it’s no surprise to find out he has racist and homophobic views and doesn’t mind sharing them. He wants everyone to know he’s a proper fighter. “Peace is just the intermission between wars,” he growls on his voice-over, with the attitude of a man who views life as a long series of battles.  He is also known to the other denizens of the pub as a national hero, the man who sparked the Velvet Revolution by throwing the first punch.

As a violent man, one of his hobbies is kicking people’s heads in. The steady stream of blokes trying to chat up the pub’s landlady Lucka (Kateřina Janečková) provides him with plenty of chances. Vandam is sweet on Lucka, who inherited the boozer from her debt-ridden mum.

One evening a more well-dressed guy than usual approaches Lucka, but he is not after her phone number or a quick bunk up. He is Mr. Milner (Václav Neužil), a slick developer who wants a million crowns from her, otherwise the joint will get bulldozed as part of the neighbourhood’s revitalisation plans.

Of course, Vandam steps up to take care of things. He genuinely cares for Lucka and helping her out might be the way to her heart. Plus he really wants to save his favourite pub…

So the racist nutjob we encounter in the first few scenes turns out to be a bigot with a heart of gold, and the fate of the pub lines up a classic save the orphanage-style plot as Vandam strives to raise the money within a week.

As the story progresses, we find out more about Vandam’s life and past. It turns out that he isn’t quite the knucklehead he first appears, with a keen interest in military history and stargazing. He leads a solitary life in the same sparse but orderly apartment that was once his family home, and we learn of a tragedy in his younger years that still haunts him. Later, we also find out that his role in the Velvet Revolution wasn’t quite as heroic as his pals seem to think…

Following his debut feature Schmitke, Altrichter directs with plenty of style and energy. The opening act is the strongest, as we meet the denizens of the North Star and hear their brazenly nationalist and xenophobic views, yelled from table to table over beers and shots. The director also finds some beauty amid the paneláky of the dreary housing projects, shooting the high rises and the spaces in between with warmth and affection. These scenes contrast nicely with Vandam’s journey to the titular street in downtown Prague, the site of Milner’s swanky office and the flashpoint of the Revolution many years before.

Unfortunately, Altrichter lacks the courage of his convictions and the film loses its way a little in the formless middle section. The drunken bigots we first meet become increasingly likeable and quirky, almost like the side characters in a Menzel movie. Just with more ethnic slurs and cuss words.

Vandam, too, becomes cuddlier the more we find out about him. The film goes from scuffling on Romper Stomperturf to drinking beer at a barbecue in Shane Meadows’ back garden. Thankfully, a jolt of violence in the third act puts the movie back on track, rediscovering its brawling energy just in time to see us home.

Adding backstory waters down Vandam’s mystique, making him a more complex character but not necessarily a more interesting one. Čermák’s performance, however, cannot be faulted. I’ve only seen him in the Gangster Ka movies previously where I had reservations about him in the lead role. There are no such doubts here. He is a hugely enjoyable presence, swaggering through every scene with barely contained aggression bubbling just beneath the surface. His performance is so addictive that it hardly matters when the film falters around him.

National Street doesn’t tell us as much about working-class life in the Czech Republic as it initially seems to promise, steering towards black comedy rather than a hard-hitting slice of social realism. And that’s OK. With the charismatic Čermák swinging punches at the heart of every scene, it is still great entertainment.