Kathy Marks: Lone operator shakes Australian sense of safety

Women offer flowers at a makeshift memorial in Sydney. Photo / AP

There was Bali, but it was Westerners - not Australians, specifically - who were targeted.

There was MH17, but the ill-fated plane was downed in a distant foreign field.

And while there had been incidents on Australian soil, such as the bombing of Sydney's Hilton Hotel in 1978, they occurred decades ago - in a bygone era, it seemed.

Of course, terrorist attacks which claimed Australian lives overseas were horrifying. But the country had grown used to thinking of terrorism as happening elsewhere.

While the Lindt cafe siege was small stuff compared with attacks in the US, Britain and elsewhere in recent years, it struck Australians in the solar plexus - unfolding in an upmarket chocolate-themed cafe in the middle of the nation's largest city 10 days before Christmas. Not just close to home, but right on Australians' doorsteps.

It's a banal observation, but it could have been any of us. I was in that cafe recently, looking for my brother's favourite Lindt bar, which isn't available in Britain. A friend told me yesterday that he frantically texted his partner, who works in Martin Place, after hearing the news reports. Then there were the customers who turned up just after Man Haron Monis locked the plate glass doors.

What took place in Sydney's CBD was truly terrifying, which is, of course, the whole point of such acts. And what made it even more so was that it was executed by a "lone wolf" - the kind of terrorist that security agencies consider their worst nightmare nowadays.

Lone wolves - such as Michael Zehaf-Bibeau, who shot dead a soldier at Ottawa's war memorial then ran amok in the Canadian Parliament, in October - are more difficult to detect than a group or network. The latter often discuss their plans in chatter that can be picked up by security forces. And, as experts have pointed out, loners require next to no kit.

All it took to bring Sydney to a standstill and strike terror into Australians' hearts was one man, a gun and a flag.

The siege was also a reminder that lone wolves come in different guises. Monis was not a young man radicalised by social injustice, or by a firebrand preacher, or by extremist propaganda on the internet. He was 50 years old, with a mainstream criminal record and a grievance about a recent conviction for sending hate mail to the families of Australian war dead.

It was the very ordinariness of this week's bloody saga that was so perturbing. Debate about a possible terrorist attack had always envisaged something spectacular, like the Sydney Harbour Bridge being blown up. Not someone walking into a cafe with a gun.

How can you guard against such things? You can't. You can only remind yourself that they are isolated incidents. But that will be no comfort to the families of Katrina Dawson and Tori Johnson, who lost their lives in such pointless circumstances.