Parliament is in mourning for Jo Cox, the first sitting British MP to be killed in 26 years

"Our memories will be forever scarred by this moment. Our hearts will always be hurt at our country’s loss. Jo Cox was the most vivacious, personable, dynamic and committed friend you could ever have. Whenever you talked to her, the compassion in her eyes and the commitment in her soul shone through. Years of public service advancing the causes she cared passionately about should have been ahead of her.

“Sarah and I were privileged to work with Jo and her husband Brendan over many years and in her tireless efforts on behalf of poor and desolate children and mothers. She she went to some of the most dangerous places in the world. The last place she should have been in danger was in her home community.

“People will say that this does not happen in Britain. This should not happen in Britain. And we must resolve that this will never again happen in Britain.

“My and Sarah’s thoughts and prayers are with Brendan and their two young children Cuillin and Lejla this evening They will have all our support in the difficult days ahead.

“For them and for those of us who were Jo’s friends, this is a devastating day. And it is a devastating blow to our democracy.”

(Source: Gordonandsarahbrown.com)

"I am heartbroken. Jo had a truly remarkable spirit and passion that shone through in her work with Oxfam and with me on our countless campaigns for women and children.

“Jo cared about everybody but she reserved a special place in her heart for the most vulnerable and the poorest citizens of the world.

“She was fearless, she was endlessly upbeat and she reached out to so many to join her cause. Her mission was to make the world a better place.

“But above all else Jo had utter devotion to her husband Brendan and their two children Cuillin and Lejla.”

"We have lost a great star. She was a great campaigning MP with huge compassion, with a big heart."

"It is right that we are suspending campaigning activity in this referendum, and everyone's thoughts will be with Jo's family and her constituents at this terrible time."

"We've lost a wonderful woman, we've lost a wonderful member of parliament, but our democracy will go on. Her work will go on. As we mourn her memory, we'll work in her memory to achieve that better world she spent her life trying to achieve."

"Jo died doing her public duty at the heart of our democracy, listening to and representing the people she was elected to serve."

"In the coming days, there will be questions to answer about how and why she died. But for now all our thoughts are with Jo's husband Brendan and their two young children."

"This is utterly shocking and tragic news, which has left everyone stunned."

"She was held in huge regard as a brilliant young woman, who had already contributed a huge amount in her time in Parliament, and today she was simply going about her job as a local MP."

"Jo fought to help the refugees from the Syrian civil war – she gave a voice to those whose cry for help she felt was not being heard."

"It changed attitudes and I know it contributed to a change in policy. She will never know how many lives she helped transform. Today, doing that job, she senselessly lost her own life."

"I am horrified by the assassination of British MP Jo Cox, murdered earlier today in her district in Northern England. By all accounts, she was a rising star. It is cruel and terrible that her life was cut short by a violent act of political intolerance.

"It is critical that the United States and Britain, two of the world's oldest and greatest democracies, stand together against hatred and violence. This is how we must honor Jo Cox -- by rejecting bigotry in all its forms, and instead embracing, as she always did, everything that binds us together."

"The incident is terrible, dramatic and our thoughts are with the people affected – the Labour lawmakers, the politicians. I don't want to connect this with the vote on Great Britain staying in the European Union."

"Deeply sad for Jo Cox and the British people. Through her it's our democratic ideals that were targeted. Never accept that!"

"I join you in expressing my deep sorrow that a young parliamentarian, who obviously was a young woman of enormous talent, has been killed in the conduct of her duties with her constituency. It is an assault on everybody who cares about and has faith in democracy. And our thoughts are profoundly with the family – her husband, her children – and with all of the British people, who I know feel the loss profoundly."

"The UK is a beacon for peaceful politics, and we hope that the British public ... can make their democratic choices serenely and in a safe way next week."

"My thoughts are with her family, her friends, and the British people. It was a true shock to me that a British politician was killed during the campaign."

"Absolutely sickened to hear of the assassination of Jo Cox. She was young, courageous, and hardworking. A rising star, mother, and wife."

"Jo was a diminutive pocket rocket from the north. She was a ball of energy, always smiling, full of new ideas, of idealism, of passion. She gave so much to Oxfam."