Hamburg is shutting up shop. Windows boarded up, manhole covers sealed.
The prime ministers and presidents have yet to arrive, but protests have already turned to violence.
Earlier this week, police used water cannon to disperse demonstrators and there have been scuffles as officers tried to clear small tented camps set up by protestors.
Last night, a Porsche garage was torched. On Thursday night a huge demonstration is planned. On Friday, protesters aim to stop world leaders getting into the summit.
At Hamburg’s police headquarters, there is an atmosphere of nervous tension. Teams of officers in minibuses drive in and out past lines of water cannon and police vans, parked up and ready for action. About 20,000 officers are on duty over the course of G20.
The police, it seems, are taking no chances. They say up to 8,000 extremists, armed with home-made weapons, are targeting the city.
“Some of these …