Greenpeace supporters Harry Westaway and brother Simon scaled the London landmark on the anniversary of the invasion on March 20 and unfurled banners which stated �time for the truth�.

The brothers, both from Lewes, East Sussex, were arrested on suspicion of causing criminal damage, and bailed to return to a London police station today.

A spokesman for New Scotland Yard said this afternoon that no further action was being taken against the men.

He declined to comment further.

Greenpeace welcomed the move. A spokeswoman said: �We are very happy that no charges are being brought against Harry and Simon for their peaceful anti-war protest at Big Ben.

�They climbed Big Ben to express their strongly-held belief that the war against Iraq was wrong and illegal.�

The brothers� seven-hour protest sparked a review of policing, and at the time they described overcoming Parliament�s defenses as �easy�.

They cleared a wall and security fence before climbing the 315ft tower.

Today Harry Westaway, 28, said criticism of the police response was �misplaced� and added: �We feel their reaction was responsible and proportionate.�

He said: �We climbed Big Ben to urge Tony Blair to come clean about why he went to war against Iraq.

�It clearly wasn�t because of WMD, as none have been found.

�It clearly went against the will of the United Nations and was illegal under international law. It has only increased the threat to Britain from international terrorism.

�Finally, it was clearly without the support of the UK public who came out in unprecedented numbers to urge him not to take us to war.

�One year on, we urge him to come clean, admit his mistakes and commit to never undertake an illegal pre-emptive war in Britain�s name ever again.�