Kim Leadbeater made the passionate call for action after a commission set up by Batley and Spen MP Mrs Cox before her death recommended that the UK needs a government-led national strategy to combat a problem which affects millions of people.
As revealed in The Yorkshire Post earlier this week, the final report of the Jo Cox Loneliness Commission found that nine million adults in the UK are often or always lonely and that loneliness is as harmful to health as obesity or smoking 15 cigarettes a day.
The economic price of loneliness is estimated to cost employers £2.5 billion every year.
Ms Leadbeater said: “Yes, government has got to play a part, that’s where policies are made and that’s where some of the money’s going to come from. But the great thing about this issue is that we can all make a difference.
“We can all go out tomorrow and knock on somebody’s door, catch up with a friend we’ve not seen for a while who might be having a tough time and we can all make a little bit of difference.”
Speaking following the report launch at Jo Cox House in Batley earlier today (Friday), Ms Leadbeater said: “On a day-to-day basis it needs to come from us - every single one of us.
“I’m really embarrassed that I didn’t know my neighbours until Jo got killed.
“And I know everybody on my street now. Because what they did, they scooped me up and looked after me when I needed it, and that just shows you the power of community.”
Ms Leadbeater said her sister developed an interest in loneliness when she found herself feeling alone as a student at Cambridge University.
She said: “We all have this outside persona that everything’s great and we’re having this fantastic time but often it’s not like that.
“Jo and I were really close when we were growing up - we did everything together as kids. When she went away to university, she entered this world of Cambridge, which was a very intimidating place for a working class northern girl.”
The report and its manifesto were drawn up after a 12-month investigation identified a “gap in national leadership on loneliness”.
The report says the “generational challenge” will only be met with concerted effort by all corners of society.
Among its conclusions, the report calls for a UK wide strategy for loneliness across all ages, led by Government, but built on the experience of others including the NHS, voluntary and community sector and business.
It says a nominated lead Minister is needed to drive action on loneliness across Government, and is calling for the development of a Family and Relationships Test, so every new Government policy is assessed for its impact on loneliness.
The Yorkshire Post exclusively revealed that Mrs Cox, the then-Labour MP for Batley, was launching the commission to investigate loneliness on the second anniversary of our Loneliness: The Hidden Epidemic campaign, in February last year.
Just four months later Mrs Cox, who pledged to “blow the lid” on the loneliness crisis, was murdered while working in her constituency.
In the months after her death, her work was taken forward by the joint commission chairs, Labour MP for Leeds West, Rachel Reeves, and Seema Kennedy, the Conservative MP for South Ribble.
Throughout the year, the Commission, which is supported by thirteen leading charities and businesses, has released evidence that showed loneliness affects people of all ages and has a profoundly damaging impact on the nation’s health, wellbeing and economy.
A Government spokeswoman said: “We welcome the work of the Jo Cox Commission and its ambition to combat loneliness. Tackling social isolation and loneliness is of huge importance to the Government.
“A number of Government initiatives already help to reduce loneliness, such as improved mental health support and funding to create new green spaces for communities, but we are committed to doing more and look forward to setting out plans in the New Year.”
Meanwhile the Royal Voluntary Service (RVS), the charity Jo Cox’s family chose to receive funding to continue her legacy after she was murdered, is launching three new projects in her former constituency to help reduce loneliness and isolation, particularly amongst older people.
RVS Chief Executive Catherine Johnstone said: “As Jo Cox said ‘loneliness doesn’t discriminate’ and over the course of the last year we have had our eyes opened to just how many of us are affected. We welcome the commission’s manifesto and agree that whilst the government has a role to play, tackling loneliness is the responsibility of all of us.”