Scottish Liberal Democrat leader Willie Rennie is to set out the “Third Way” alternative to Britain under Boris Johnson or independence.
He will use his virtual Liberal Democrat conference speech to set out his vision for the country’s future on Sunday, focusing on Europe.
Mr Rennie will brand a split from the UK for Scotland as being a repeat of the “mistakes of independence”.
He is set to say: “There is a big lesson from Brexit.
“We know breaking up the European Union has been chaotic and painful and it has only been around for 40 years.
“The United Kingdom has been around for 300 years. Just imagine how difficult breaking it up would be.
“So let us not repeat the mistakes of Brexit with independence.
“Let’s work with our neighbours – in Europe and the UK.
“Let’s unite for progress. That’s the third way.”