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.
PA