To help Londoners voice their opinions about the UK Government's proposals to cut Legal Aid, the team behind the Sound Off For Justice campaign, which opposes the plans, have kitted out a fleet of London black cabs with iPads and iPhone 4s.

They've also turned them into "Sound Off" booths, each of which able to record complaints about the possible removal of Legal Aid support while the disgruntled passengers make their way around the capital. Those messages will then be sent directly to Justice Secretary, Kenneth Clarke.

An online petition will also be able to be signed on the move, using the 3G-capable iPads in each taxi.

And the tech angle doesn't even end there: The public will be able to track (and then presumably flag down) the "Sound Off" cabs on Twitter by checking out the dedicated feed @soundoffjustice. Passengers will be offered a free ride to a location of their choice (within Zones 1 and 2) in return for speaking their mind.

So, no trips to Edinburgh then...