Last updated at 14:52 14 April 2008

Banksy pulled off an audacious stunt to produce what is believed to be his biggest work yet in central London.

The secretive graffiti artist managed to erect three storeys of scaffolding behind a security fence despite being watched by a CCTV camera.

Then, during darkness and hidden behind a sheet of polythene, he painted this comment on 'Big Brother' society.

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'One nation under CCTV': CCTV (pictured top right) failed to catch Banksy

Yesterday the scaffolding gang returned to remove all evidence - again without the camera operator stopping them.

The work, above a Post Office yard in Newman Street near Oxford Circus, shows a small boy, watched by a security guard, painting the words: 'One nation under CCTV.'

Andrew Newman, 35, a businessman from Dulwich, who works locally, said: 'It was only on Sunday morning that the Post Offices guys realised what had happened.'