Ms Cox was elected to the seat of Batley and Spen at the last general election in 2015.
She was a Remain supporter in the referendum and both official campaigns have suspended their operations as a mark of respect following the attack on her.
Jo Cox's husband Brendan: 'Jo believed in a better world and fought for it every day'
Brendan Cox, the MP’s husband, has issued a statement about her death. He says she would have wanted everyone to unite “to fight against the hatred that killed her”.
Today is the beginning of a new chapter in our lives. More difficult, more painful, less joyful, less full of love. 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 every day of her life with an energy, and a zest for life that would exhaust most people.
She would have wanted two things above all else to happen now, one that our precious children are bathed in love and two, that we all unite to fight against the hatred that killed her. Hate doesn’t have a creed, race or religion, it is poisonous.
Jo would have no regrets about her life, she lived every day of it to the full.