Jo Cox, the Labour MP for Batley and Spen, has died after being shot and stabbed in her constituency.

Ms Cox, 41, had been holding her weekly advice surgery when the incident occurred and was reportedly left bleeding on the pavement by her attacker.

She was then taken to the Leeds General Infirmary in a critical condition.

Police have now reported that Ms Cox has died following the incident.

Prime Minister David Cameron has tweeted: "The death of Jo Cox is a tragedy. She was a committed and caring MP. My thoughts are with her husband Brendan and her two young children."

The MP for Witney had planned to hold an anti-Brexit rally in Gibraltar later today but cancelled it on hearing the news.

He said: "It's right that all campaigning has been stopped after the terrible attack on Jo Cox. I won't go ahead with tonight's rally in Gibraltar."

Before the announcement of her death Nicola Blackwood, the MP for Oxford West and Abingdon, had tweeted: "Every thought with @Jo_Cox1 & her loved ones right now - prayers for strength & safe recovery."

Elsewhere Ed Vaizey, the MP for Wantage, said it was "terrible news" and Victoria Prentis, the MP for Banbury, said: "Terribly shocked and saddened to hear the news about Jo Cox MP. My thoughts and prayers are with her and her family."

Between 2001 and 2009 Ms Cox was head of policy for the charity Oxfam.

As head of the charity's Brussels office she spearheaded Oxfam's campaign for trade reform. In 2005 she joined Oxfam GB as head of advocacy, based at its head offices in John Smith Drive, Cowley.

The charity has descrived her as a "passionate advocate" on humanitarian issues including the conflicts in Darfur and the Democratic Republic of Congo.

Her commitment to humanitarian issues led her to become head of humanitarian campaigns for Oxfam International in New York in 2007 for two years.

Max Lawson of Oxfam, who worked closely with her, said: "Jo was a diminutive pocket rocket from the north.

"She was as a ball of energy, always smiling, full of new ideas, of idealism, of passion. She gave so much to Oxfam.

"She was an inspiring leader, really bringing the best out of all of us, always positive, always believing we could win and always passionate for change. She was particularly brilliant at bringing huge energy to our campaigning around the desperate humanitarian crisis in Darfur."

Oxfam GB's Chief Executive, Mark Goldring, said:"Oxfam is proud of the role that Jo played in our work over a decade. Many of our colleagues remember her fondly. The rest of us followed her work with admiration.

"She never lost her passion for peace, justice and equality. Everyone is deeply shocked to hear the news. Our thoughts and sympathies are with Brendan and Jo's family at this difficult time."

Oxford City Council leader Bob Price said: "I am devastated by this shocking news. MPs are very much in the public arena and vulnerable to this type of unprovoked attack.

"Jo Cox was known to many people in Oxford from her time at Oxfam and our hearts go out to her, her family, and all her friends and colleagues in Yorkshire."

The Muslim community in Oxford have also paid tribute to "a great MP, a lovely wife, caring mother, and woman of integrity".

Dr Ramzy, chairman of the Oxford Islamic Information Centre said: "Our heart goes to Jo’s family. This was a premeditated and brutal killing of an MP whose goal and aim was to help the poor and needy around the world. Her compassion and kindness, and commitment to humanitarian causes, including the plight of the refugee children, will form part of her legacy and will be remembered."

"My heart, thoughts and prayers goes out to Jo’s husband and her little children, deprived so cruelly of their mother.

"I pray to Almighty God to bless her soul and house her in paradise, as she was an exceptionally a good woman." 

Ms Cox's husband Brendan, former director of policy and advocacyat Save the Children, issued a statement about her death in which he called on the world to "unite to fight against the hatred that killed her".

He said: "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."

Oxford East MP Andrew Smith has also spoken of the time someone threatened to kill him.