Tens of thousands of Scottish independence supporters are due to march through Glasgow in the first of a series of protests over the coming year.
The All Under One Banner (AUOB) march will leave Kelvingrove Park at 11:30 GMT and head to Glasgow Green.
A mass rally that was due to be held afterwards has been cancelled after rain and high winds were forecast.
Glasgow City Council has estimated that about 100,000 people will take part.
But organisers have predicted the total could reach 300,000, which they say would be a record for one of their events.
The “emergency” march was organised in the wake of last month’s general election, which saw the pro-independence SNP win 48 of the 59 seats in Scotland while the Conservatives won a majority across the UK as a whole.
It is the first of eight marches that the grassroots AUOB group plans to hold across Scotland over the coming year as activists aim to increase the pressure for independence.
The organisation has staged several similar marches and rallies in town and cities across Scotland over the past five years.
AUOB stressed that the Glasgow march would definitely go ahead despite the cancellation of the rally, with the group tweeting: “If we let some Scottish rain stop us marching then we’ve no chance. The march is on.”
Neil Mackay, one of the event’s organisers, said: “Organising outdoor events in Scotland in winter is always difficult and is always subject to our weather.
“We had a number of great speakers lined up for the rally, so it is a pity it will not now take place. We have apologised to the speakers for the cancellation and they have all been very understanding and supportive.
“All Under One Banner looks forward to an important and impressive march taking place on Saturday.”
Scottish voters backed remaining in the UK by 55% to 45% in a referendum in 2014 – but Nicola Sturgeon, the SNP leader and Scotland’s first minister, says she wants to hold another vote on independence later this year.
That currently looks unlikely to happen because the UK government has made clear it will not transfer the powers that Ms Sturgeon says would be needed to ensure any referendum is legal.
The first minister has ruled out holding an unofficial referendum, similar to the disputed one in Catalonia in 2017, as she does not believe it would lead to independence regardless of the result.
Ms Sturgeon has never attended an AUOB march, although she did speak at a rally organised by the pro-independence National newspaper in Glasgow’s George Square in November. It was the first time she had spoken at a major independence rally since 2014.
Another AUOB march will be held in Glasgow in May, with similar events scheduled for Arbroath, Peebles, Elgin, Kirkcaldy, Stirling and Edinburgh.