Those of us who had hoped that the infamous Munich massacre was simply a terrible one-off stand were deluded. Though our delusion is nowhere near the obscene extremities of those who perpetrate these unspeakable atrocities, alas, Munich was not the end, just the beginning.

It also spawned the two words which remain indelibly scarred on the face of sport. Black September.

It was just after 4am when eight hooded members of the Palestinian terrorist organisation of that name jumped over the eight-foot fence surrounding the Olympic Village and headed for 31 Connollystrasse, the block which housed the male Israeli athletes, coaches and officials. The Munich Massacre proceeded to tear the Olympics apart.

Now, four decades later, massive, often oppressive security has become as integral a part of all subsequent Games as the 100 metres, with Britain, in the wake of the London bombings which came a day after the 2012 Olympics had been won in Singapore, spending more than £1 billion ($1.5 billion/€1.4 billion) to protect its Games.

Moreover, just about every other sporting event of any consequence has required a strong security presence, even though this is not always evident to the public.

Black September is the grim reminder that it has to be worth it.

Who would have thought, for instance, that over 40 years on a tennis match would have to be played out under a massive security blanket heavy with armed militia?  

But such will be the situation when (and perhaps still even if) this weekend’s Davis Cup final between Great Britain and Belgium takes place in Ghent, a pleasant city in a nation on red alert and primed for attack at any time.

Or that a British boxer defending his world title would have to express unease at being a possible terrorist target in Canada because he has a French-sounding surname.

“It is extremely sad, it's frightening,” says the former Olympic champion James DeGale, who encounters a French-Canadian, Lucien Bute, in French-speaking Quebec on Saturday night.

With France, and anything French, now firmly on the hit-list of the Islamic loonies who have caused such desecration in Paris and Mali, an African country with a huge French influence, his apprehension is understandable. And deeply saddening.

However, for both the Andy Murray-led GB Davis Cup squad and IBF super-middleweight champion DeGale, the first Briton to convert an Olympic boxing gold to a professional world title, the show will go on.

As it must if sport is to remain part of the defiant coalition, epitomised by players and fans alike at the England-France football match at Wembley last week, that is essential to crush terrorism.

When Fred Perry and Bunny Austin last won the Davis Cup for Great Britain, 79 years ago, it was a defining moment for British sport. Victory in Ghent will be again, especially as the pressure is not confined to the court.

Ghent, where the final is due to start on Friday, is only 35 miles from Brussels, a capital virtually under lockdown because of a “serious and imminent” threat of a Paris-style attack, according to the Belgian prime minister.

The 13,000-seat Flanders Expo is sold out for all three days of the final, with more than 1,000 British fans due to attend.

International Tennis Federation President David Haggerty says he is "greatly concerned" by developments, but that preparations for the tie would continue. As they should.

Former British number one Tim Henman, though, has cancelled his plans to attend the final.

He was quoted as saying: “I was going to go, but I am not going any more.

"I was going to take my three girls, I was going to go with my family. With the train and then going over there, I just thought 'is it really worth the hassle for them?' So we are going to be watching at home."

Again, quite understandable. However, DeGale’s family - father, mother, sister and partner - say they will be with him as usual in Quebec.

He says: ”What happened in Paris was a terrible, terrible thing. I am sure there will be a lot of emotion running through the crowd. I try not to think about people attacking sports events. I am just going there to do a job.”

DeGale’s French connection is through his father Leroy, whose ancestors worked on a plantation in Grenada, then a French dependency. Those antecedents took the name DeGale, which was that of the plantation owner.

There is no doubt that in the light of current - and past - events sport is not bomb proof, so to speak, when it comes to terrorism.

In 2016, France is due to host the quadrennial European Football Championships.

Just Fontaine, the Frenchman who holds the record of scoring the most goals in a single World Cup, said that his homeland should renounce the right to stage the competition.

He said: "I am very afraid that this black Friday could be repeated. I think we cannot guarantee the safety that is required to host such a big event."

I find this rather defeatist. True, sport remains a target because its principal events are popular and also because huge numbers of people gather in a small area. This increases the likelihood of multiple deaths.

Remember that if a security guard had not spotted one of the terrorists trying to enter the stadium in Paris last Friday with a bomb strapped to his body, the numbers killed would have escalated, a frightening prospect.

I recall a British security expert advising the International Olympic Committee once opining privately that, after Munich 1972, events like the Olympics would not be targeted as terrorism is supposedly dependent on the element of surprise, and they are now heavily protected. This no longer appears to be the case.

The Boston Marathon bombing was an example of this, as was the France-Germany football match.

You may think that next year’s Olympics will be relatively safe because Isis and other extremist elements have no argument with Brazil.

But like all sport it is vulnerable because wherever large crowds gather a successful attack resulting in a multitude of deaths would have maximum publicity impact for their warped cause.

Sport must continue to absorb the terrifying lesson of Munich 1972. Terrorists will never play the game.