Sir Keir Starmer has postponed a speech on Scottish devolution amid concerns it could be overshadowed by the end stages of Brexit trade negotiations with the EU.
The Labour leader had been due to detail his plans to revive party support in Scotland during an address to Edinburgh University on Friday.
But this has been derailed by the drama surrounding trade negotiations with Brussels, with the potential this week for Boris Johnson to declare whether there will be a deal.
Would-be attendees were emailed: “Due to the likelihood of a clash with major Brexit developments, Keir Starmer is no longer able to deliver the John P Mackintosh Lecture this Friday.
“We know that Keir remains fully committed to delivering this lecture. We hope to re-schedule in the new year and we will be in touch when a new date has been arranged.”
Scotland is key for Sir Keir’s chances of ever forming a majority government, with Labour support there being slashed by the SNP in recent elections.
The SNP’s deputy leader in Westminster, Kirsten Oswald, said: “The Tories’ Brexit chaos is not a reason to postpone decisions on Scotland’s future – quite the opposite.
“No amount of constitutional tinkering of the kind proposed by Labour would protect Scotland from Brexit or a Tory power grab – only independence will do that.”
The date of the speech was confirmed before Sir Keir went into self-isolation, meaning if it did go ahead he would have to deliver it from home.
He entered quarantine because a member of his office staff tested positive for Covid-19.
His official spokesman said the Labour leader received a negative result on Tuesday but would follow the rules and continue isolating for another seven days.
He said Sir Keir, who took part in Prime Minister’s Questions remotely on Wednesday, took the test at home after it was provided by parliamentary authorities.