The Finchley Road is one of the busiest thoroughfares heading out of London. It leads traffic north past Lord's Cricket Ground and the multimillion-pound houses of some of the country's richest hedge-fund managers all the way to the M1. At three in the afternoon it's always pretty slow going, but on this particular summer Monday the traffic was almost at a standstill.
This was partly because the normal three lanes going north had been cut down to one. But it was also because of drivers slowing down to a crawl so they could gawp at the massive police operation unfolding on a busy corner of the road.
Police vehicles - both cars and menacing armoured trucks - jammed up two lanes. Dozens of armed officers in bulletproof vests were standing ready, waiting to be called inside an anonymous-looking building. From the sheer manpower and weapons on display it looked like the capital was under another terrorist attack. But while this was the Metropolitan Police's most ambitious operation in its 180-year history, it had nothing to do with national security. Only hours before, at a special briefing, teams from SCD6 (the Economic And Specialist Crime unit) and C019 (Specialist Firearms Command) hunkered down with technicians armed with angle grinders and drills. Also present were dog handlers, their animals trained to sniff out guns, drugs and explosives.