A year to the day after Jo Cox, the MP for Batley and Spen, was murdered, hundreds of children from nine local schools gathered on a sunny green in the West Yorkshire town of Heckmondwike to sing in her memory. “We will shout it from the rooftops and sing it everyday,” they sang, as their teary-eyed parents looked on. “We are all equal, all different, all unique.”

The performance was the first of a weekend of events in Cox’s former constituency and across the UK to remember the MP’s murder by a neo-Nazi and to honour her belief that “we have far more in common than that which divides us”.

“Seeing these children is making me think of [Jo’s] children today and how sad it is that she’s not with them,” said Kate Gavaghan, a local swimming teacher whose 11-year-old son was among those performing the song, which was written by a local music teacher. “Hopefully, these kids singing these songs will grow up carrying forward that message.”

The Great Get Together, which has been organised by Cox’s husband, Brendan, and their family, aims to be the biggest expression of national unity since the Diamond Jubilee. The 110,000 events planned from Friday to Sunday include street parties, BBQs, picnics, coffee mornings, tea parties and iftars (the meal breaking the Ramadan fast).

The huge number of get-togethers planned for the weekend showed people had “a real appetite for something positive”, said Kim Leadbeater, Cox’s sister, speaking during the opening of the newly named Jo Cox Conference Centre at Upper Batley high school on Friday morning.

“The world feels like quite an unstable place at times, and it feels quite scary at the moment,” she says. “We’ve had a lot of really horrendous things happen in the past 12 months, whether it’s the Manchester attack or the London attack, or this horrendous fire this week, but what you see is that when these things happen, people do come together.”

Her sister, said Leadbeater, would have been in her element this weekend. “She’d be doing exactly what we’re doing, which is dashing around trying to get to as many events as possible and speak to as many fantastic people as she possibly could.”

Cox’s parents are also planning to keep themselves busy on the anniversary of their daughter’s murder. “It’s what Jo would have wanted,” said her mother, Jean. “She wouldn’t have wanted us to sit at home and do nothing.”

Pupils at Cockshut Hill school in Birmingham form a human chain to spell out the murdered MP’s name to mark the Great Get Together weekend. Photograph: The Challenge/Silversky Media/PA

“We’re going to try to get around as many schools, mosques, churches [as possible]. The Brownies, the Guides, everybody,” added Gordon Leadbeater, her father. “It gives us strength.”

Kim Leadbeater said the past year had flown by and admitted that the reality of her sister’s death had yet to sink in. “I think we’ve probably – for me and Brendan – been a bit too busy, but I think that has been our way of coping, keeping focused on organising this weekend and lots of fantastic events.

“I think what that means for me personally is that I haven’t given myself any real time to process what happened and that’s probably going to come over the summer when things calm down a bit. And that’s going to be tough and I have to be ready for that.”

At about 12.50 on Friday – exactly a year since Cox was pronounced dead after being stabbed and shot outside the library in Birstall – the MP’s family were joined by members of the public in the nearby village square. Religious leaders, schoolchildren and people on their lunch break took part in decorating a temporary structure, designed to be an area of reflection, with flowers and drawings.

Organisers of the weekend are keen to ensure the focus is not on the horror of the MPs’ death, but Kim Leadbeater admitted there would inescapably be “an awful lot of sadness”.

“I’ve been crying this morning, but we have to be able to do that,” she said. “I think it’s very important, particularly for the people of Birstall, who were there that day. They saw things they shouldn’t have had to see.”

She said that while her family was dealing with a very personal loss, many people in the town of Birstall were dealing with acute trauma. “For them today will be particularly hard because they’ve been trying to get on with their lives over the past 12 months.”

“So much has happened over the last year that it feels like it could have been two or three,” said Tracy Brabin, who was elected as MP for Batley and Spen in a byelection following her friend’s death. “It’s been so tumultuous, not just for me in my life, but for the nation and our community.”

“I’m so proud to come from this area,” she said. “We’ve gone through so much and come out the other side a year later saying ‘We will not be cowed. We will celebrate our differences.’”