JO Cox is the first member of the House of Commons to be murdered in office since 1990, when Ian Gow became the last in a string of MPs to die at the hands of Northern Irish terror groups.
A former private parliamentary secretary to Margaret Thatcher, Eastbourne MP Mr Gow was killed by an IRA car bomb at his Sussex home at the age of 53.
Before him, the MP for Enfield Southgate Sir Anthony Berry died in the IRA bombing of Brighton's Grand Hotel, where Mrs Thatcher was staying for the 1984 Conservative Party conference.
The IRA also claimed the life of Ulster Unionist Party MP Robert Bradford, who was shot dead aged 40 while holding a constituency surgery in a Belfast community centre in 1981.
And the Irish National Liberation Army claimed responsibility for the murder of former Northern Ireland secretary Airey Neave, whose car was blown up as he drove out of the parliamentary car park at Westminster in 1979.
No other sitting MPs have been murdered in the post-war period, though Labour's former MP for Accrington Walter Scott-Elliot was killed by his butler in 1977, many years after leaving Parliament, and former Tory MP Sir Richard Sharples was assassinated by a militant group in Bermuda 1973, while serving as the island's Governor.
Meanwhile, Labour MP Stephen Timms, who survived a violent attack at his constituency surgery has paid tribute to Jo Cox.
Mr Timms was stabbed twice in the stomach in 2010 by a 21-year-old Islamist radical, who said she was taking revenge for his vote in favour of war in Iraq.
His injuries were described as life-threatening, but he recovered to return to his parliamentary duties as MP for East Ham a month later.
Speaking after Ms Cox's death was announced, Mr Timms said: "I am shocked and appalled by the terrible news this afternoon. Jo was a wonderful MP, and a wonderful person. I - and everybody else - had been very impressed since her election last year.
"I would like to express deepest condolences to Jo's husband Brendan and their family.
"Although details remain unclear, it seems Jo was simply carrying out her job on behalf of her constituents. The circumstances appear very similar to those when I was attacked six years ago."
Mr Timms's attacker Roshonara Choudhry was given a life sentence for attempted murder and possession of a knife.
