It may have taken nearly three years, 22,000 litres of paint and 44,000 man-hours, but contractors are approaching the final push in giving London's Tower Bridge a shiny new coat.
The two famous "bascules" – drawbridges, to you and me – are set to be painted for the first time since the early 90s, requiring them to remain lowered for six months. To mark the occasion, I have been invited to operate the bridge – one of the last times it will be raised before March 2011.
It's 5.30pm, and a few hundred commuters are about to get very, very grumpy with me. I am petrified. "Stand by, bridge staff," I announce into the Tannoy. "Stopping road traffic."
The man with a Zeus-like beard to my left flicks a switch. Two sets of traffic lights turn to red, barriers are lowered, and four crammed car lanes slow to a halt. An entire commuter corridor is paralysed.
One commuter, however, makes a break for it: a lone city gent vaults a barrier and gallops across the now deserted bridge to the southern side. I titter nervously, relieved the sprinter hadn't started his run later on in the proceedings. But David Duffy, the hirsute bridge driver, has seen it all before. "The funniest thing," he says, "is when you get the canoodling couple standing in the middle of the bridge, totally oblivious."
We're standing in a small control-room on the bridge's north-eastern corner. In front of us is a panel fitted with about 20 yellow buttons, a series of CCTV screens, and a large computer monitor. But it is the black lever nestling in the middle of all this that really runs the show. With its two speeds, "creep" and "fast", this is what actually gets the bascules moving. The lever sends an electrical signal to a valve, allowing oil into a pipe, which drives a hydraulic motor, which in turn drives the bridge.
"Do you want to look professional?" asks Duffy, a former Airbus engineer. "Don't move the lever out of 'creep' until both green lights are showing on the monitor." This, he says, makes the two bascules rise in unison.
Sweaty-palmed, I grip the lever gingerly before yanking it straight into fast mode, stopping suddenly, then starting again. The bascules pop up, briefly hesitate, and then jerk skywards once more. Gulp. Still, 90 seconds later, and we're there: bascules raised at 35 degrees.
"Your arm got a bit tired, didn't it?" Duffy suggests, generously, before switching on the water traffic lights.
Tower Bridge opens its gates 1,000 times a year, with any boat taller than 30ft allowed to sail through. Today it's the Waverley – the world's last seagoing paddle steamer. Decks crammed with waving tourists, her masts clear the bascules, and I breathe easy. "Doesn't take much to move 2,500 tonnes of steel, does it," says Duffy.
