Gordon Brown attends July 7 event

Before families and friends laid their own tributes, Gordon Brown led a small procession to lay wreaths in the memorial garden beside Kings Cross Station at the exact time the first bomb struck two years ago.

The Prime Minister, former Culture Secretary Tessa Jowell, London Mayor Ken Livingston, Transport Commissioner Peter Hendy, Tim O'Toole of London Underground and the Mayor of Paris, Bertrand Delanoe, all bowed their heads in silence for several minutes before making way for survivors and relatives to pay their respects.

A short message attached to the flowers Mr Brown laid read: "In remembrance and with deepest sympathy".

Relatives and those who lived through the bombs that struck at the heart of London in 2005 then moved forward, some alone and others supported by friends and family, to lay their own bouquets - one of which had been fashioned into the figure seven.

Many simply stood for a moment to remember, brushing away their tears, but for others the emotion was too much and they collapsed into each others arms.

The brief poignant act of remembrance was in stark contrast to last year's public ceremonies and was organised in line with the wishes of the families involved, according to organisers.