Brexit will do for independence what Thatcherism did for devolution, one of Plaid Cymru’s MPs will say later.
Jonathan Edwards will tell his party’s conference in Swansea the vote to leave the EU has driven a “sledgehammer through the post-devolution period”.
Independence has risen up the Welsh political agenda following a series of marches held across Wales.
“We can finish the job started by devolution,” Mr Edwards is expected to say.
Plaid will hold the second day of its autumn conference at the city’s Grand Theatre.
On Friday, party leader Adam Price said he believed a referendum on Welsh independence would be held by 2030 – while demanding £20bn in reparations from Westminster.
Mr Edwards will tell delegates: “I remember writing a university dissertation trying to explain the differences between the 1979 and 1997 Welsh referenda, and why Wales had gone from being overwhelmingly opposed to devolution to marginally voting in favour in the space of 18 years.
“The main reason was the Thatcherism inflicted upon Wales immediately after the first referendum. The people of our country yearned for a degree of protection via self-government.
“The Brexit referendum drove a sledgehammer through the post-devolution period in Welsh history and now the stakes in the game have been raised considerably.
“On the one hand Wales as a political nation will be re-subsumed by Westminster. On the other hand, we can finish the job started by devolution and become a normal independent European country.”
The MP for Carmarthen East and Dinefwr adds: “I am more convinced now than ever that Brexit, whatever happens from here in, will be for independence what Thatcher was for devolution.”
Voting for Plaid’s next chairman will finish on Saturday.
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.