The day finally came, after more than a year in which Canberra had become the city the pandemic forgot.

A hopefully short, sharp and targeted lockdown has broken the tension in the capital. No longer must we wonder which day will the coronavirus arrive. We now have our answer.

It has been well understood for a while that just one case active in the community would lead to a lockdown in Canberra. Four have already been identified, with more expected to come.

If you happened to arrive here from somewhere else in the world this week, the reaction might seem strange. Over-the-top even. All this for just one case? But in a city where life has been lived mostly without restrictions, there was hardly any other option. The lockdown was the right call - and the extra cases proved it.

Not even the ACT's nation-leading vaccination rollout, hamstrung by federal government's supply rather than the willingness of Canberrans' to get jabbed, could keep the virus out.

READ MORE COVID-19 NEWS:

There will most likely be more cases in the coming days. The exposure sites have left scores potentially exposed to the possibly deadly virus, some in high-risk settings.

The sight of hundreds of unmasked, and probably unvaccinated, young people, shoulder to shoulder, having the time of their lives in a nightclub at the weekend is now bittersweet. They weren't to know, personally living within the rules.

But with a border as porous as the territory's, it's hardly surprising the virus made it here. The Chief Health Officer, Dr Kerryn Coleman, expects the virus to have come from Sydney, although investigations were still continuing on Thursday afternoon.

Chief Minister Andrew Barr said he had no regrets over not putting in place a Canberra regional border bubble early, and that it was unlikely it would have made a difference anyway.

READ MORE COVID-19 NEWS:

Canberra needs to accept the hard border always was an impossibility. Criminal investigations would virtually stop. A good chunk of the territory's health workforce would be shut out.

But the border arrangements announced on Thursday, which offer a standing exemption to people in surrounding postcodes to come to the ACT for essential reasons, seems like a good compromise. Hopefully, it serves to cocoon the capital while this outbreak is brought under control, and possibly afterwards as NSW quells its outbreak.

Canberra is a lucky place, with a healthy population of rule followers. We like to line up in an orderly way. We do the right thing, and follow instructions from experts. This will be key to keeping the lockdown short, and preventing as many people from getting sick as possible.

Most Canberrans have not seen the extensive suffering that coronavirus creates up close. And now is not the time to start.

Our coverage of the health and safety aspects of this outbreak of COVID-19 in the ACT and the lockdown is free for anyone to access. However, we depend on subscription revenue to support our journalism. If you are able, please subscribe here. If you are already a subscriber, thank you for your support. You can also sign up for our newsletters for regular updates.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: