At least 22 people were killed, including children, in a suicide bomb blast at the end of a pop concert by US star Ariana Grande in Britain's third city of Manchester.
Police say they believe Monday night's attack, the deadliest on British soil in 12 years, was carried out by one man who had died at the scene.
The country has been hit by a number of other terror strikes in recent years:
- 2017: Westminster Bridge attack -
March 22: Five people are killed and more than 50 are 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 at the scene. Investigators describe the lone-wolf attack as "Islamist related terrorism".
- 2016: Lawmaker murdered -
June 16: British Labour lawmaker Jo Cox is shot and stabbed to death by a pro-Nazi sympathiser just days before the historic vote to leave the EU. Far-right white nationalist Thomas Mair is later sentenced to life in prison for her murder.
- 2015: London underground stabbing -
December 5: A paranoid schizophrenic stabs two people at London's Leytonstone Underground station, two days after Britain's first air strikes on the jihadist Islamic State group in Syria. The knifeman, Somali-born Muhaydin Mire, 30, is sentenced to life behind bars. The police say the incident is a "terrorist" attack.
- 2013: British soldier slain -
May 22: British soldier Lee Rigby, 25, is hacked to death by two Britons of Nigerian descent near an army barracks in London. Witnesses say the attackers encouraged them to film the scene as they shouted "Allah Akbar" ("God is greatest") before being injured and arrested by police. In February 2014, Michael Adebolajo, 29, is sentenced to life in prison for the murder while Michael Adebowale, 22, receives a minimum of 45 years behind bars.
- 2009: Northern Ireland shootings -
March 2009 sees a sudden resurgence of political violence in Northern Ireland with two soldiers shot dead outside their barracks by republican militants as they went to collect a pizza delivery, the first such slaying since 1997. Two days later a police officer is shot dead by a different paramilitary republican faction.
- 2007: Glasgow airport attack -
June 30: Two men in a burning vehicle ram into the main terminal of Glasgow Airport in Scotland. An Indian 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.
- 2005: Suicide bombers hit London transport -
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.
The London attack took place just a day after the city was awarded the 2012 Olympics.