The Boston Marathon bombing simply reaffirms how vulnerable sport is to terrorist atrocity, lunatic act, lone publicity-seeker or political point-scorer.

London 2012 security cost more than £1bn and the security budget for Glasgow 2014 has now more than trebled to £90m. Yet the Boston incident which left three dead and some 170 injured demonstrates how impotent even serially security-conscious events are, whether the threat be a deranged activist or global terrorist organisation.

I've witnessed dra0matic Olympic breaches. In Munich (1972) Palestinian Black September guerrillas attacked the Israeli team leaving 11 athletes dead; in Atlanta (1996) a bomb exploded in Centennial Park; and in Athens (2004) an unfrocked priest leapt on the Olympic marathon leader.

Munich is often said to have been the end of sporting innocence, but sport has been a platform for causes. The Ancient Olympics is revered for a truce which halted wars. Yet this was conspicuously broken in 364BC when Elis made a surprise attack on the Olympic sanctuary during the wrestling contest, attempting to regain control of the lucrative site from a rival city. Was this the first Olympic terror attack?

Security costs rocketed after Munich and were partly responsible for Montreal, the 1976 hosts, taking some three decades to pay the bills.

In the absence of responsibility for Boston being claimed by an organisation, it would be wise not to jump to conclusions. US authorities suspected white supremacist terrorists of the Atlanta Centennial Park attack in 1996. Then they blamed a security guard. It took seven years to hunt down a former army explosives expert who is now serving life without possibility of release. He was an anti-abortionist.

The 2004 marathon assailant was also a pro-life lobbyist. An unfrocked Irish priest tackled the Olympic marathon leader. It was also he who had cavorted on track in the midst of the British Grand Prix and who was flattened by former race director Dave Bedford when he tried to disrupt the London Marathon.

Sport is always vulnerable. Witness last year's Boat Race demo and Emily Davison's Derby stunt 100 years ago this year which resulted in fatal injuries from the King's horse.

Boston is not even the biggest marathon atrocity. A Tamil Tiger bomber killed 12 and injured more than 100 at a race celebrating Sri Lanka's new year. Cricket in the sub-continent has been victim of several terrorist attacks.

Being on the wrong side politically can be fatal. Iraqi Olympic officials and competitors have been gunned down, dozens have been kidnapped and never seen again, while Libyan sports officials have been tortured by what the UK would characterise as a terrorist regime.

Mere threat can even be catastrophic: the IRA caused the 1997 Grand National to be delayed by two days. It was not inappropriate to delay and check, yet I believe sport (and life) should never bow to terrorism, for to do so is to allow terror to prevail. The right to play together, and socialise together, is the essence of freedom itself. We must learn to live with it.

The biggest security threat with which the world's oldest marathon had previously to deal was summarily defused by its long-time Scottish race director, Jock Semple. Before women were allowed to run the distance, this fiesty, carnaptious figure physically tackled Kathy Switzer when she gatecrashed Boston, and threw her out.

Yet this former Clydesdale Harrier had long been donating money and trophies to men's and women's athletics in Scotland. These included one for the first Scot in the international cross country championship. Clydesdale still gets monthly income from investments he donated.

The perpetrator of the Boston atrocity should perhaps be more afraid of the shade of Semple than the FBI.

AND ANOTHER THING

Sir Chris Hoy has chosen his home city for a grand announcement tomorrow. Cycling's worst-kept secret seems to be details of his retirement.

Hoy told me in Beijing, after 16 races unbeaten and a third gold medal which made him Britain's greatest Games' competitor in a century, that he hoped his body would stand the strain long enough to permit him to end his career in Glasgow. So it will be a trying day for a self-confessed emotional man who said it had been hard competitively, learning to "operate like a robot . . . and when to turn it off and on".

He now faces what to do with the rest of his life, a consideration I recall when I was penning the career obituary of Sebastian Coe in 1990, following his sixth place in the 1990 Commonwealth 800m final.

So where might Hoy go from here? At least he goes on his own terms, unlike Coe, with fading powers evident. It is to Hoy's credit if he has read the signs.

One always suspected Coe would be drawn to politics. While there's no comparable pointer with Hoy, but a common denominator: the certainty of success in whatever they tackled.

Heading the world athletics body (now within Coe's grasp) is perhaps predictable, but Lord Coe? Or landing the Olympics for Britain? Pat McQuaid, the world cycling body's now-discredited president, while presenting Hoy's third Beijing gold, asked if he had been forgiven for removing the kilometre from the Olympic programme, the event in which the Scot had won gold in 2004.

That underlines life's unpredictability, but here's a snapshot of the future: Hoy as president of the discredited International Cycling Union (UCI). It desperately needs a man of his status, charisma and integrity to restore its reputation.