Boris Johnson has dismissed the prospect of a second Scottish independence referendum and questioned "what it's all meant to be about".
The prime minister called for a "focus on the issues that really matter" and urged Scottish voters to ignore "pointless constitutional wrangling".
"I think endless talk about a referendum without any clear description of what the constitutional situation will be after that referendum is completely irrelevant now to the concerns of most people, who I think want us to beat this pandemic and come through it strongly together," he said.
Mr Johnson on Thursday visited a COVID vaccine laboratory in Livingston, where French company Valneva has begun large-scale manufacturing of its vaccine candidate.
But his trip attracted criticism, with Scottish First Minister Nicola Sturgeon among those to question whether his travel would be deemed "essential" under coronavirus restrictions.
Asked why he had made the 400-mile trip during a lockdown, Mr Johnson said he had come "as prime minister of the whole country to thank our hardworking officials and public servants across the whole of Britain who are doing fantastic work".
His visit came after a recent poll of Scots found that 49% supported Scottish independence compared to 44% who favoured remaining in the UK.
Meanwhile, the SNP recently published an 11-point plan on how they intend to bring about another independence referendum.
If Ms Sturgeon's party wins a majority at this year's Scottish Parliament elections, the first minister has said the SNP will hold an independence vote, regardless of whether Westminster consents to the move.
Mr Johnson declined to answer on whether he would boycott a referendum in Scotland, if the UK government had not approved it.
"My focus is on defeating the pandemic, I believe that should be the focus of everybody in this country," he said.
"I believe in the power of doing things together.
"Going on and on about another referendum - we don't actually know what that referendum would set out to achieve.
"We don't know what the point of it would be - what happens to the army? What happens to the Crown? What happens to the pound? What happens to the Foreign Office? What happens to the security services?
"Nobody will tell us what it's all meant to be about."
The prime minister said he was "inclined to stick with what they said last time", as he referred to the No vote by Scottish voters at the 2014 independence referendum.
Mr Johnson refused to comment on the description of Ms Sturgeon as a "moanalot" by Jacob Rees-Mogg, the Leader of the House of Commons.
"I don't want to be distracted by any kind of petty, personal, political issues," the prime minister said.
"This is a time for the country to come together, beat the virus, protect the NHS, save lives."
The UK has secured 60 million doses of the Valneva vaccine, should it be approved by the regulator.