As I write this on Friday afternoon, my workmates are crowded around the windows of our 19th-storey office, watching police cordon off Canary Wharf underground station in order to examine a suspect package. It's just the latest in a series of events over the past 24 hours that has seen three explosions on trains, an explosion on a bus and, this morning, a man shot dead at Stockwell, my local tube station.
Typically, Londoners are responding to it with their usual mix of bravado, humour and nonchalance, many seeing it yet again as an excuse to retreat to the nearest pub for reinforcements - but the racks are starting to show.
When the first bombs went off on the morning of Thursday 7th July, most of us were on our way to work. Stranded outside tube stations, with mobile phone networks down and no access to information, we were confused and afraid. What was going on? Rumours flew - seven blasts, thousands of casualties - and we automatically feared the worst.
But as it turned out, the reality, though terrible, wasn't as bad as many had imagined. After the smoke had cleared, people realised that, as tragic as events had been, relatively few people had been affected - and that it could have been a helluva lot worse.
London quickly, defiantly bounced back and resumed a state of near-normality. Many seemed to be of the opinion, "Well, it's happened now, thank god that's over and done with." And everyone had a tale or joke to tell about the day the terrorists struck - "I can smile about it now, but at the time it was terrible", as Morrissey might say.
The Dunkirk spirit was in evidence everywhere. Almost immediately, a website, we're not afraid, was launched - and was just as swiftly followed by a (much better) spoof retort, iamfuckingterrified.com.
But then, two weeks to the day, they struck again, this time at lunchtime, when many of us were at work. Rather than waiting anxiously for the news to filter through, we followed it on TV and on the Internet and - now knowing the drill - immediately checked in with friends and family.
Initial alarm at the 7/7 pattern repeating itself (three trains and a bus, blasts north, south, east and west) turned to irritation ("Don't say we have to walk home again") and cynical amusement ("Haha, the idiots couldn't even get it right!) once it was learned the explosives apparently failed to detonate. But this time the laughter sounded hollow.
The shooting at Stockwell station this morning has only served to drive home the fact that 7/7 was not an isolated event - that there are perhaps hundreds of hardcore fundamentalists ready and willing to commit atrocities, even die, for their cause. Though we can find some reassurance in statistical reality - in a city of 7.5 million, there's more chance of you being hit by a bus than being on one that explodes - it's cold comfort indeed.
Is London going to become the frontline? Do we, like Israel, simply have to learn to live with an ever-present threat? Basically, yes - what else can we do? Of course we'll continue to laugh and joke about it, and seek comfort and courage in publichouses - this is London, after all - but secretly we're shitting ourselves. As for me, that decision made back in May to book a flight home to NZ in October is increasingly looking like the right one.
Now, if you'll excuse me, I'm off to the pub.