Oil spill prevention unit out in force in London today to #tellshell not to destroy the Arctic

It's action stations at the petrol stations. Right now, teams of Greenpeace volunteers are shutting Shell forecourts across London and Edinburgh. The teams are fanning out across the two cities, going station to station shutting down the pumps. In total, over 100 forecourts will be out of action, and it's all because Shell has a fleet of vessels on its way to the Arctic where they'll be drilling for oil in the next few weeks.

We're also broadcasting throughout the day on a special online TV channel. We'll be going live on the hour, every hour, with the latest updates from our make-shift studio in the warehouse of our north London office. We've never done anything like this before and, like all live TV, there will undoubtedly be hiccups, but it will be a lot of fun.

It's part of the global week of action against Shell that kicked off with the occupation of the head office in the Hague – as well as our live TV channel, follow #tellshell on Twitter for all the latest from around the world.

Here's how the teams are shutting down Shell. Each station has a big off switch – it's the bright red box up on the wall that turns off the pumps if there's an emergency, like a fire. With the switch off and the fuse removed, it can't be turned on again without a new fuse (and the teams will be posting the fuses back to Shell – waste not, want not). The pumps themselves are also going to be chained up with bicycle locks, so even if the pumps are turned back on they can't be used.

This is a protest about Shell's Arctic drilling plans, not about car use in general (and we're all for making cars more efficient so the demand for oil is reduced) so at each station closed, the teams will be posting directions to the nearest open petrol station.

You can register your outrage at Shell's reckless endeavours as well. Shell has it's Loyalty Club for regular customers, so we've cooked up a Disloyalty Card – print it off, fill it in and post it to Shell free of charge, using Shell's own freepost address.

As we've been reporting throughout the year, Shell wants to see if there's oil off the Alaskan coast and the Noble Discoverer – the ship occupied by Lucy Lawless and other activists in New Zealand back in February – is in Dutch Harbour, waiting to begin operations. (It looks like the Noble Discoverer has problems of its own – it ran aground on Saturday.)

We've also been cataloguing the risks posed by an oil spill in Arctic waters. The presence of icebergs makes it dangerous in the extreme – if a big one is heading towards a rig, the only course of action is to get out of the way, fast. And the short drilling season before the sea ice closes in means clearing up a spill would be all but impossible.

No one has found oil in the Arctic yet and with good reason – the risk makes it expensive and dangerous but with the easy-to-reach oil running out, oil companies are prepared to take that risk in the name of profit.

It's because of these increasing threats to the Arctic – not just from companies like Shell, but from industrial-scale fishing fleets and the tussling between governments over the strategic importance of the region – that we've declared a global sanctuary north of the Arctic circle.