From the Times of London:

“The police stopped an armoured personnel carrier outside The Times offices and arrested all the occupants. It is understood they had planned to join the protests.”

From the Guardian:

“11 protesters who turned up at the protest in an armoured personnel carrier were arrested in connection with the possession of police uniforms and road traffic offences. The latter group are understood to be anarchists known as the Space Hijackers who had come to make their feelings felt through the medium of street theatre.”

Space Hijackers twitter: twitter.com/spacehijackers
Space Hijackers web: spacehijackers.co.uk