John McDonnell launches Labour election platform in Glasgow

Shadow chancellor John McDonnell. Picture: Kirsty O'Connor/PA Wire

Mr McDonnell will say the party has been presented with the “opportunity of a lifetime” to change the UK political landscape.

Mr Leonard clashed with Mr McDonnell earlier this year when the Shadow Chancellor suggested Labour at Westminster would not block a second referendum on independence in contravention of party policy in Scotland.

“We are presented with the opportunity of a lifetime to change the direction of political travel in the UK in a way not seen since the 1980s,” Mr McDonnell is expected to say.

“Our time is coming and it may be coming quicker than anyone expected.

“That’s why I’m here, with an election maybe just around the corner, to support Richard Leonard and talk about what we can achieve together.

“[There is] a far-right nationalist Conservative Party that will stop at nothing to deliver a no-deal Brexit, screwing over whoever it wants in the process, continuing austerity and failing to lift a finger to tackle the climate emergency.

“And north of the Border, a Scottish National Party government who have passed on Tory austerity to Scottish councils and users of public services and who, despite all the rhetoric, have failed to deliver the investment needed so the jobs building our sustainable future are coming to Scotland.”

Mr Leonard will suggest the Prime Minister has “abused” his power in suspending Parliament.

“Democracy requires continual renewal,” he will say.

“The Scottish Parliament is 20 years old this year and this week, we have witnessed Boris Johnson close down Parliament.”