A commission set up by MP Jo Cox before she was murdered has concluded the government should create a national strategy to combat loneliness.
The Jo Cox Loneliness Commission concludes that some nine million adults in the UK suffer from constant loneliness, which is as harmful to health as obesity or smoking 15 cigarettes a day.
"There is currently a gap in national leadership on loneliness," the report said.
"While central Government cannot solve loneliness alone, it can play a role in galvanising the key players, catalysing action, assessing and comparing progress, and holding those who need to act accountable."
In the report, the commission calls for a UK-wide strategy for loneliness across all ages, led by government "but built on the insight, expertise and capacity of many others including the NHS, voluntary and community sector and business".
As part of this, the report says, a lead minister should be appointed to drive action on loneliness across government and be accountable to parliament.
The commission also calls for a further development of the current Family Test, through which government policies are assessed to make sure they support strong and stable families, to become a Family and Relationships Test.
The report says: "Tackling loneliness is a generational challenge that can only be met by concerted action by everyone - governments, employers, businesses, civil society organisations, families, communities and individuals all have a role to play. Working together we can make a difference."
The cross-party commission was established by Mrs Cox when she was Labour MP for Batley and Spen.
Its work, which is supported by 13 charities and businesses, was carried forward after she was murdered outside her constituency office in Birstall, West Yorkshire, in June 2016.
The final report will be presented in the constituency on Friday by the joint commission chairs, the Labour MP for Leeds West, Rachel Reeves, and Seema Kennedy, the Conservative MP for South Ribble.
The MPs will be joined by Jo's sister Kim Leadbeater.
Earlier this week, Ms Reeves described loneliness as having "escalated from personal misfortune into a social epidemic".
She said the architect of the Welfare State, Sir William Beveridge, would have added it to his list of giant evils - want, disease, squalor, ignorance and idleness - if he was starting today.
The joint chairs said: "This report shares the ideas the commission has worked on over the past year, and it challenges national government to step forward and lead a renewed push to tackle loneliness.
"But we know that loneliness will not end until we all recognise the role we can play in making that happen.
"Jo always looked forwards, not back: she would have said that what matters most now are the actions, big and small, that people take in response to the commission's work. That's a responsibility for all of us."
The reports notes that three-quarters of GPs say they see up to five patients every day who are lonely and that loneliness is estimated to cost employers £2.5 billion every year.
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."