Forensic investigators search on the platform at Parsons Green tube station in London - REUTERS
London - 15 September 2017: Police have described Friday's attack on a London Underground train, in which an "improvised explosive device" injured at least 22 people, as a terrorist incident.
This makes it the latest in a string of terror strikes on the country in recent years. Here is a recap of some of the others.
A van ploughs into people leaving late-night prayers at a mosque in Finsbury Park in north London on June 19; one man dies in the incident and 11 others are injured.
The driver, 47-year-old Darren Osborne, is charged with terrorism-related murder and attempted murder.
Three men wearing fake suicide vests mow down pedestrians with a van at a popular nightlife hub around London Bridge and then leave the vehicle to stab at people. They are killed by police.
Eight people are killed and about 50 are hurt. The Islamic State group claims responsibility.
A suicide bomber blows himself up outside a pop concert by teen idol Ariana Grande in Manchester, killing 22 people and injuring 116. Seven of the victims were under the age of 18.
The attack was carried out by 22-year-old Salman Abedi, a Manchester-born university drop-out of Libyan origin, and claimed by the Islamic State group.
Five people are killed and more than 50 wounded when a man rams his car into pedestrians on Westminster bridge in London before crashing into the barriers surrounding parliament and then stabbing a police officer to death.
The attacker, 52-year-old British Muslim convert Khalid Mahmood, is shot dead by police. Investigators describe the lone-wolf attack as "Islamist related terrorism".
A paranoid schizophrenic stabs two people at London's Leytonstone Underground station on December 5. The knifeman, Somali-born Muhaydin Mire, 30, is sentenced to life behind bars. Police say the incident is a "terrorist" attack.
British soldier Lee Rigby, 25, is hacked to death in May by two Britons of Nigerian descent whom witnesses say shouted "Allah Akbar" ("God is greatest") before being injured and arrested.
Michael Adebolajo, 29, is later sentenced to life in prison for the murder while Michael Adebowale, 22, receives a minimum of 45 years behind bars.
Two men in a burning vehicle ram into the main terminal of Glasgow Airport in Scotland in June. An Indian man driving the car suffers serious burns and later dies. The passenger, Iraqi doctor Bilal Abdulla, 29, is jailed in December for at least 32 years for plotting to murder hundreds of people.
On July 7 four British suicide bombers inspired by Al-Qaeda attack London's Underground network and a bus during rush hour, killing 52 people, as well as themselves, and wounding 700.
It was the deadliest attack on British soil since a Pan Am airliner blew up over the Scottish town of Lockerbie, killing a total of 270 people including 11 on the ground, in 1988.