You can continue to follow the story on BBC News here and get the latest updates from the BBC Politics Live team.
Detained man 'did gardening chores', neighbours say
Pritti Mistry
BBC News Online
Neighbours said they did not think he had a job or drove a car, and described how he would do gardening chores for local people.
David Pickles said he didn't know of any connection between his neighbour and Jo Cox.
Quote Message: He's lived there longer than me and I've lived here since 1975. I still can't believe it. He's the last guy I would have thought of. "He's just quiet. He kept himself to himself. He lived by himself. He's been on his own for about 20 years. "I've never seen a lot of people visiting or anything like that, but he likes gardening. He did a lot of people's gardens round here. But he did it quietly. from David Pickles Neighbour
He's lived there longer than me and I've lived here since 1975. I still can't believe it. He's the last guy I would have thought of. "He's just quiet. He kept himself to himself. He lived by himself. He's been on his own for about 20 years. "I've never seen a lot of people visiting or anything like that, but he likes gardening. He did a lot of people's gardens round here. But he did it quietly.
'We all grieve with you' - former Labour leader Ed Miliband
Pritti Mistry
BBC News Online
Former Labour leader Ed Miliband praised MP Jo Cox's widower, Brendan Cox's "extraordinary dignity, love and compassion". He added: "Brendan - we all stand with you and grieve with you."
Getty ImagesCopyright: Getty Images
Quote Message: My heart breaks for the loss of Jo Cox and for Brendan and their kids. She was so full of life and joy. Words feel hopeless right now. from Ed Miliband Former Labour Party Leader
My heart breaks for the loss of Jo Cox and for Brendan and their kids. She was so full of life and joy. Words feel hopeless right now.
Former MEP pays tribute to 'beloved friend'
Pritti Mistry
BBC News Online
Former Labour MEP Baroness Glenys Kinnock paid tribute to "my beloved friend Jo Cox".
Quote Message: The tragic death of Jo Cox is devastating. I send all my love to Brendan, their children and her devoted parents. from Baroness Glenys Kinnock Former Labour MEP
The tragic death of Jo Cox is devastating. I send all my love to Brendan, their children and her devoted parents.
Arrested man described as a 'loner' by neighbours
Pritti Mistry
BBC News Online
A man held over the attack on Labour MP Jo Cox has been described as a "loner" by neighbours.
Local man Tommy Mair, 52, was detained by police near his home in Birstall, West Yorkshire.
Neighbours said he lived on his own for the last two decades since the deaths of his mother and grandmother.
US Department of State 'shocked and appalled'
US Department of State's spokesman John Kirby says it is "shocked and appalled" by the murder of Jo Cox.
Former PM Tony Blair says Jo Cox death 'huge loss'
Labour former prime minister Tony Blair said: "This is absolutely tragic. Such a pointless and savage act of hatred contradicts everything Jo lived for and worked for."
Quote Message: She is a huge loss to British politics. My heart goes out to Brendan and their children."
She is a huge loss to British politics. My heart goes out to Brendan and their children."
Jo Cox's maiden speech
I've just seen this on Twitter, it's Jo Cox's maiden speech.
BBCCopyright: BBC
Former US congresswoman pays tribute to Jo Cox
Former US Congresswoman for Arizona Gabrielle Giffords, who was the victim of an assassination attempt in 2011, also paid tribute.
'Beginning of a new chapter' - Brendan Cox, widower of Jo Cox MP
Pritti Mistry
BBC News Online
Brendan Cox, the husband of murdered Labour MP Jo Cox, paid tribute to his wife and said: "Today is the beginning of a new chapter in our lives. More difficult, more painful, less joyful, less full of love."
PACopyright: PA
Quote Message: I and Jo's friends and family are going to work every moment of our lives to love and nurture our kids and to fight against the hate that killed Jo. Jo believed in a better world and she fought for it everyday of her life with an energy, and a zest for life that would exhaust most people. from Brendan Cox Husband of Jo Cox
I and Jo's friends and family are going to work every moment of our lives to love and nurture our kids and to fight against the hate that killed Jo. Jo believed in a better world and she fought for it everyday of her life with an energy, and a zest for life that would exhaust most people.
Flowers laid at the statue of Joseph Priestley
People have been laying flowers in tribute to Jo Cox in Birstall, at the statue of Joseph Priestly.
BBCCopyright: BBC
BreakingThe Queen to write to Jo Cox's widower
A Buckingham Palace spokesman said the Queen will write privately to Mr Cox.
Council buildings to fly flags at half-mast
Kirklees Council says flags on civic buildings will fly at half-mast to mark the killing of MP Jo Cox:
Vigil in Parliament Square
We understand that an impromptu vigil is happening in Parliament Square this evening.
Jo Cox is the first member of the house of commons to be murdered in office since 1990
Jo Cox is the first member of the House of Commons to be murdered in office since 1990, when Ian Gow became the latest MP 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 aged 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.
Watch: Full West Yorkshire Police media briefing
Shortly after 17:00 this evening, West Yorkshire Police gave a press conference about the attack on Batley and Spen MP Jo Cox. You can see it in full below.
Live Reporting
Oli Woodcock
All times stated are UK
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Latest PostMP dies in 'horrific' shooting attack
MP Jo Cox dies from her injuries after she was shot and stabbed in an attack at her West Yorkshire constituency.
Read moreOur Live coverage has finished
Pritti Mistry
BBC News Online
Our live courage has ended for the day.
You can continue to follow the story on BBC News here and get the latest updates from the BBC Politics Live team.
Detained man 'did gardening chores', neighbours say
Pritti Mistry
BBC News Online
Neighbours said they did not think he had a job or drove a car, and described how he would do gardening chores for local people.
David Pickles said he didn't know of any connection between his neighbour and Jo Cox.
'We all grieve with you' - former Labour leader Ed Miliband
Pritti Mistry
BBC News Online
Former Labour leader Ed Miliband praised MP Jo Cox's widower, Brendan Cox's "extraordinary dignity, love and compassion". He added: "Brendan - we all stand with you and grieve with you."
Former MEP pays tribute to 'beloved friend'
Pritti Mistry
BBC News Online
Former Labour MEP Baroness Glenys Kinnock paid tribute to "my beloved friend Jo Cox".
Arrested man described as a 'loner' by neighbours
Pritti Mistry
BBC News Online
A man held over the attack on Labour MP Jo Cox has been described as a "loner" by neighbours.
Local man Tommy Mair, 52, was detained by police near his home in Birstall, West Yorkshire.
Neighbours said he lived on his own for the last two decades since the deaths of his mother and grandmother.
US Department of State 'shocked and appalled'
US Department of State's spokesman John Kirby says it is "shocked and appalled" by the murder of Jo Cox.
Former PM Tony Blair says Jo Cox death 'huge loss'
Labour former prime minister Tony Blair said: "This is absolutely tragic. Such a pointless and savage act of hatred contradicts everything Jo lived for and worked for."
Jo Cox's maiden speech
I've just seen this on Twitter, it's Jo Cox's maiden speech.
Former US congresswoman pays tribute to Jo Cox
Former US Congresswoman for Arizona Gabrielle Giffords, who was the victim of an assassination attempt in 2011, also paid tribute.
'Beginning of a new chapter' - Brendan Cox, widower of Jo Cox MP
Pritti Mistry
BBC News Online
Brendan Cox, the husband of murdered Labour MP Jo Cox, paid tribute to his wife and said: "Today is the beginning of a new chapter in our lives. More difficult, more painful, less joyful, less full of love."
Flowers laid at the statue of Joseph Priestley
People have been laying flowers in tribute to Jo Cox in Birstall, at the statue of Joseph Priestly.
BreakingThe Queen to write to Jo Cox's widower
A Buckingham Palace spokesman said the Queen will write privately to Mr Cox.
Council buildings to fly flags at half-mast
Kirklees Council says flags on civic buildings will fly at half-mast to mark the killing of MP Jo Cox:
Vigil in Parliament Square
We understand that an impromptu vigil is happening in Parliament Square this evening.
Listen: Yvette Cooper MP pays tribute to Jo Cox MP
Oli Woodcock
BBC Local Live, Leeds
Yvettte Cooper, Labour MP for Normanton, Pontefract, Castleford & Knottingley has been paying tribute to Jo Cox MP.
Yvette spoke to Andrew Edwards on BBC Radio Leeds following the death of the Batley and Spen MP earlier today.
Vigil for Jo Cox in Birstall tonight
IMF Brexit report postponed
Bloomberg reporting that the International Monetary Fund has postponed its Brexit report by 24 hours
Jo Cox is the first member of the house of commons to be murdered in office since 1990
Jo Cox is the first member of the House of Commons to be murdered in office since 1990, when Ian Gow became the latest MP 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 aged 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.
Watch: Full West Yorkshire Police media briefing
Shortly after 17:00 this evening, West Yorkshire Police gave a press conference about the attack on Batley and Spen MP Jo Cox. You can see it in full below.