Britain held a minute of silence on Tuesday to mark the 10th anniversary of al Qaeda-inspired attacks in which four suicide bombers killed 52 people across London’s transport system.
The commemoration came just four days after the country came to a standstill to mourn a massacre of mainly British tourists at a resort in Tunisia last month.
The government and security services warned the threat of further attacks remains severe.
“Ten years on from the 7/7 London attacks, the threat from terrorism continues to be as real as it is deadly – the murder of 30 innocent Britons whilst holidaying in Tunisia is a brutal reminder of that fact. But we will never be cowed by terrorism,” Prime Minister David Cameron said in a statement.
Relatives of the victims, survivors, royals and senior politicians fell silent as they remembered those killed in the bombings.
In the early hours of July 7 2005, less than 24 hours after it was announced London would host the 2012 Olympic Games, four young British Muslims travelled from northern England to the capital, where they detonated homemade bombs hidden in rucksacks on three underground trains and a bus during the morning rush-hour.
They killed themselves and 52 other people and wounded around 700 others. Citizens from Poland, Israel, Australia, France, Italy, Afghanistan, Nigeria, New Zealand and a Vietnamese-American were among the victims.
On Tuesday, Cameron and London mayor Boris Johnson stood silently, heads bowed, before laying wreaths at the 7/7 memorial in Hyde Park, where victims’ families and survivors were later joined by Prince William, Queen Elizabeth’s grandson.
The main service of remembrance took place at St Paul’s Cathedral, where petals fell from the cathedral’s dome and the names of those killed were read out.
At underground stations where victims were brought to the surface, floral tributes were laid on Tuesday on steps leading down to the platforms.
Esther Hyman, 46, whose sister Miriam was killed on the No. 30 bus when it was blown up at Tavistock Square, told Reuters many young people seemed unaware of the bombings.
“The events of 7/7 do seem to have slipped out of public consciousness,” said Hyman, who with her mother last week launched a programme to help teach school pupils about the attacks and to steer them away from violent extremism.
Britain is currently on its second highest alert level of “severe”, meaning a militant attack is considered highly likely, mainly due to the danger the authorities say is posed by Islamic State fighters and Britons who have joined them.
Cameron’s government is planning new laws to combat extremism among the country’s 2.8 million Muslims and to give security services extra surveillance powers. Critics say these are an assault on freedoms.
Mark Rowley, Britain’s most senior counter-terrorism police officer, said Islamic State was creating an “enormous” list of potential targets, focused on propaganda value rather than high-impact complex attacks.
“The terrible events in London on 7 July, 2005 are enduring reminders of the reality of what MI5 is striving every day to prevent,” Andrew Parker, head of Britain’s domestic spy agency, said in a statement.