Remembrance services to mark the tenth anniversary of the July 7 attacks have started.
David Cameron and Boris Johnson laid wreaths at the permanent memorial to the 52 victims killed in the atrocity in Hyde Park, central London.
The Prime Minister and Mayor of London paid their respects at 8.50am. At that time a decade ago, a series of explosions hit the capital's transport network.
Survivors and relatives of victims are attending other services at stations in the capital.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe also laid a wreath during the short, sombre ceremony in Hyde Park.
Speaking earlier, Mayor of London Boris Johnson said the four suicide bombers had "failed in their aim".
He said the terrorists "didn't in any way change the fundamentals of London and what makes this city great", adding: "Indeed, it's gone from strength to strength in the 10 years since.
"I think most people would say that London has become even more cosmopolitan, even more welcoming."
But Mr Johnson said today people have to remember that "the problem has not gone away", adding: "We're as ready as we think we can be, and as you can imagine there are preparations going on all the time in the event of all kinds of attacks."
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here