Amid fears that Britain has been struck by terror again, here are some of the terrible events suffered by the country at the hands of extremists in recent years:
:: May 22, 2017: Twenty-two people - including children - are killed and around 59 injured during a suspected terrorist bombing at a pop concert in Manchester.
It is thought a lone suicide bomber detonated an improvised explosive device as crowds of music fans, many of them youngsters, left the Manchester Arena following a performance by US artist Ariana Grande.
:: March 22, 2017: Five people are killed when an Islamist extremist launched a car and knife attack in central London.
Khalid Masood drove a hired car over Westminster Bridge, near the Houses of Parliament, mounted the pavement and hit pedestrians before crashing into railings outside the Palace of Westminster.
He stabbed Pc Keith Palmer, 48, to death and also killed US tourist Kurt Cochran, Romanian tourist Andreea Cristea, 31, plus Britons Aysha Frade, 44, and 75-year-old Leslie Rhodes. Masood was shot dead by police.
:: June 16, 2016: Labour MP Jo Cox is murdered outside her constituency office in Batley, West Yorkshire.
The mother-of-two, 41, was shot and stabbed multiple times by right-wing extremist Thomas Mair. He was later handed a whole-life prison sentence for her murder.
:: December 5, 2015: A lone attacker attempts to behead a passenger during an Islamic State-inspired rampage in the ticket hall of Leytonstone Underground station in east London.
Somali-born Muhiddin Mire targeted strangers at random during the attack on December 5 2015 before slashing fellow passenger Lyle Zimmerman, 56, with a knife.
The schizophrenic was sent to Broadmoor Hospital after being given a life sentence with a minimum term of eight years for attempted murder.
:: May 22, 2013: Fusilier Lee Rigby is murdered by Islamic extremists Michael Adebolajo and Michael Adebowale.
The 25-year-old serviceman was walking near his barracks in Woolwich, south-east London, when the pair rammed him with his car before attempting to hack off his head with knives.
The killers were jailed for life at the Old Bailey in February 2014.
:: June 30, 2007: Ttwo men inspired by Islamist extremism ram a 4x4 laden with petrol and propane tanks into the main terminal of Glasgow Airport. One of the attackers died in the incident and five people were injured.
:: July 7, 2005: Four suicide bombers kill 52 and injure hundreds of others in blasts on the London Underground network and a bus.
Twenty-six died in the bombing at Russell Square on the Piccadilly line, six in the bombing at Edgware Road on the Circle line, seven in the bombing at Aldgate on the Circle line, and 13 in the bombing on a bus at Tavistock Square.