Marcin Reszka is a nice chap. He asks me to emphasise this point. But, goodness, he can simulate viciousness when he wants to. Reszka is an instructor in krav maga, a martial art cum defence technique that is in the news because at the weekend it emerged that a company called Parli-Training was offering instruction in the art to anxious MPs and their staff.

In the wake of the killing of Jo Cox and with MP Jess Phillips resorting to installing a panic room at her constituency office following threats, the issue of safety is high on the agenda among parliamentarians. Parli-Training ran a course offering what the company calls “urban krav maga”, which it defines as “practical, quickfire techniques to use against potential day-to-day attacks”. “It’s disarming and running,” says a spokeswoman for the company. “All you are doing is buying valuable time to flee.”

The distinction Parli-Training draws between urban krav maga and military krav maga – the techniques are most associated with the Israel Defense Forces (IDF) – is largely bogus. “Disarming and fleeing” pretty well sums up the essence of krav maga. Avoiding a fight is the best defence of all but, if a fight does start, the exponent of krav maga sets out to make it nasty, brutish and short. As I type this, I can still feel a twinge in the windpipe, which is where Marcin Reszka comes in.

Reszka, 35, spent three years in the Polish army before coming to the UK. He has worked as a doorman, but is now a full-time krav maga instructor. Krav maga, which means “contact combat” in Hebrew, was a method of streetfighting developed by Imi Lichtenfeld in Bratislava in the 1930s to enable Jews to protect themselves against fascist gangs. Lichtenfeld fled the Nazis in 1940, eventually reached Palestine, became chief instructor for physical fitness with the IDF and built the techniques of krav maga into the forces’ training.

Stephen Moss blocks a blow. Photograph: Graeme Robertson for the Guardian

Lichtenfeld died in 1998, but his associates, acting rather like yoga masters, have passed on the code. Reszka learned krav maga in the Polish army and now teaches it through his company Krav Maga Tactics, although he operates under the umbrella of Krav Maga Global, whose chief instructor Eyal Yanilov studied with Lichtenfeld. Learning to gouge someone in the eyes or stun them with a sudden thrust to the windpipe has a long and distinguished lineage.

Reszka is giving me an early-morning lesson in the back room of an office unit on an industrial estate in south London – very krav maga. After a conventional warmup, we get down to business. We simulate an altercation in the street. He advances; I put my hands up. He keeps coming; I shout as loudly as possible – the aim in everything you do in krav maga is to disorientate the opponent and wrest back the initiative. Shouting doesn’t do the trick; he throws a punch and tries to get in a position to headbutt me; I block the punch, throw a straight right myself and kick him in the balls. Eyes, throat, groin – krav maga emphasises your opponent’s most vulnerable areas and targets them mercilessly.

Targeting the throat is incredibly effective. When the tables are turned and I do the advancing, the shock of a two-fingered jab to my windpipe sends me tumbling to the floor. It’s called an “educational block” because it educates me that this person is not to be messed with. It may alone be enough to defuse the danger in the situation. It certainly works with me: I am thenceforth ultra-wary of Reszka, who clearly takes his job very seriously.

Krav maga is one of the best training methods for reality Marcin Reszka

“Krav maga is one of the best training methods for reality,” he says. “It is more practical than traditional martial arts, and tries to give a little more edge to the drills and scenarios.” The ultimate aim is to enable you to handle yourself under the sort of stress you would experience if you were attacked in the street.

“The instructor will try to make you feel really uncomfortable to bring your heart rate up,” says Reszka. When it is up, the adrenaline will be flowing and you will have great strength, but that has to be married to the defence techniques that have been drilled into you and will be retained in your “muscle memory” no matter what level of stress and danger you face. That’s the theory, anyway.

We move on to headlocks. I get Reszka into one, and he demonstrates how – with my arms locked round his neck – I am the one who is vulnerable. He jabs the fingers of one hand into my eyes and, with the other hand, pushes me to the floor. One of the advantages of targeting the eyes and the windpipe is that it doesn’t need much brute strength. It will, for instance, give a woman a fighting chance if she is attacked by a much stronger man. Speed of execution and knowing where to concentrate the attack are everything. Shouting as you launch your counter-attack is recommended: more disorientation.

‘If an attacker has a knife, you only have moments to mount your defence.’ Photograph: Graeme Robertson for the Guardian

Reszka then shows me how to resist an attacker with a knife. Parry the thrust with your forearm, being careful to avoid the blade, throw a punch simultaneously, launch a kick or a knee to the groin and, while he is doubled up and groaning, get the hell out of there. Krav maga assumes there may be multiple attackers, so at all times you have to be scanning the area around you for sudden attacks from behind.

When Reszka demonstrates the techniques, his speed is incredible: the counter-attack comes in a great flurry; the fight may only last seconds. If an attacker has a knife, you only have moments to mount your defence. If a couple of thrusts with a knife get through, you may be incapable of further resistance. Speed of thought and movement are everything.

Despite the odd technical deficiency (and a dodgy knee), I have learned a lot in an hour. About 40% of Reszka’s clients are learning krav maga for their jobs: police officers who want to be more streetwise; prison guards who fear knife attacks; bodyguards; doormen. The other 60% are doing it for fitness, to feel safer on the streets and to boost their confidence. Krav maga is empowering and, as I limp out of the makeshift gym, I really do feel a better, stronger person. Albeit one who, after that jab to the throat, is having some difficulty speaking.

• This article was amended on 19 August 2016 to correct the number years Reszka spent in the Polish army before coming to the UK.