There will be a referendum on Welsh independence by 2030, Plaid Cymru leader Adam Price has said.
Speaking to BBC Radio Wales, he said a referendum would take place “definitely in the next decade”.
He said “things are accelerating” and “the UK as we know it could cease to exist in a short few years”.
It comes ahead of Plaid’s party conference in Swansea, where he will unveil policies aimed at lifting 100,000 children out of poverty.
He will say the party will lead a “decade of transformation” if it wins power at the next assembly election
They include free universal childcare for children aged one to three, and extra money for low-income families.
The party says it will provide detailed costings alongside its manifesto for the 2021 election.
Other policies to be outlined at the conference include providing a job guarantee for young people aged 16 to 24 and offering free social care for all.
“A new determination is needed, not just to manage Wales’ problems, but to fix them,” Mr Price will say.
“We’ll make Wales not just a great country to grow up in, but a decent place to grow old in.
“Our new cradle-to-grave promise to the Welsh people will see us finally deliver a seamless National Health and Care Service with social care free to all who need it.”
Labour announced a similar social care policy for England at its annual conference in Brighton last month.
“If Labour can promise to England what Scotland already has, then why don’t they do it when they are actually in government in Wales?” Mr Price will add.
Mr Price will also call for a £20bn fund for Wales, from the UK government, to be spent over 10 years delivering “a decade of transformation”.
Plaid Cymru is hoping to build on its performance at May’s European elections when the party came second in Wales behind the Brexit Party but ahead of Labour.
It was the first time Plaid had beaten Labour in a Wales-wide election.
Speaking ahead of the conference, Mr Price claimed “people’s natural allegiances are unravelling”, adding this had been a “terrific” year for the party.
Conference delegates will be asked to approve the party’s Brexit policy.
Mr Price wants the party to campaign at any upcoming general election on a platform of halting the Brexit process altogether if there is the prospect of a no-deal exit from the EU.
However his preference remains holding a second referendum.
Party members will also have the opportunity to vote for Plaid Cymru’s next chairman.
The incumbent Alun Ffred Jones is being challenged by Dr Dewi Evans.
Dr Evans has expressed support for independent assembly member Neil McEvoy, who was expelled from the party in March 2018.
Plaid Cymru has four MPs, 10 assembly members and one MEP.