IT was not a question of "if" but of "when" London would suffer a terrorist atrocity.

Indeed, it is a hard to believe that the capital had previously avoided such an attack in the four years since the horrors of September 11.

We all knew an attack on London was inevitable - former Metropolitan Police Chief Sir John Stevens told us so a year ago - but it was business as usual until the dreaded day came.

That day arrived yesterday and, with hindsight, its timing was not so surprising. It came as world leaders met in Gleneagles to try to find a solution to world poverty and global warming. And it came the day after London had joyously been chosen to host the 2012 Olympic Games.

The terrorists chose a time of hope and optimism to inflict their misery and devastation. But, as Ken Livingstone said, their victims were not powerful political leaders, but ordinary people of different colours and religions.

Those responsible are not freedom fighters. They are indiscriminate cowards who do not care who they kill.

And London, along with every other potential target, must not let them win. It must quickly return to business as usual and look to the exciting times ahead when the greatest sporting event will bring together the countries of the world in peace.

At the weekend, Britain will stage an official day of remembrance to mark the 60th anniversaries of Victory in Europe and Victory in Japan.

We will remember the bravery of those who restored peace and preserved our freedom. It is a time to redouble our determination to stand up to those who seek to undermine our way of life.