The country has been hit by a number of other terror strikes in recent years:
May 2017: Manchester Arena bombing
A suicide bomber blows himself outside a pop concert by teen idol Ariana Grande in Manchester in northwest England, 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 dropout of Libyan origin. The attack was claimed by the Islamic State group.
Manchester residents honour victims with bee tattoo
March 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: Politician 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.
British soldier Lee Rigby was attacked and killed by two men in the Woolwich area of London in 2013. Source: Ministry Of Defence
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.
We are certainly all on edge: Bishop
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.
