British Prime Minister Boris Johnson heads to Scotland on Thursday in a bid to stem growing support for another independence referendum by arguing that the COVID-19 pandemic has shown the benefits of staying together.

The bonds that tie England, Wales, Scotland and Northern Ireland together in a $3 trillion economy have been severely strained by both Brexit and Johnson’s handling of the coronavirus outbreak.

Opinion surveys show that a majority of Scots would now back independence, though Johnson has repeatedly said that now is not the time for another referendum that could break apart the more than 314-year-old union between England and Scotland.

Ahead of his visit, which was criticised by Scottish nationalists, Johnson said that Scotland as a part of the United Kingdom gained access to a coronavirus vaccine developed by the University of Oxford and the shots are being administered by the shared armed forces, who are creating 80 new vaccine centres in Scotland.

“We have pulled together to defeat the virus,” Johnson said. “Mutual cooperation across the UK throughout this pandemic is exactly what the people of Scotland expect and it is what I have been focussed on.”

Scotland’s First Minister Nicola Sturgeon criticised Johnson’s trip, questioning whether his reasons for visiting are “really essential” and arguing it sets a bad example to the public.

Sturgeon, who runs Scotland’s semi-autonomous government, is hoping a strong performance by her Scottish National Party in an election for the country’s devolved parliament in May would give her the mandate to hold a second referendum.

If Scotland voted for independence it would mean the United Kingdom would lose about a third of its landmass and almost a tenth of its population – just as the world’s sixth-biggest economy is grappling with the impact of Brexit.

Johnson, who would have to agree to a new referendum, has said there is no need for a new vote after independence was rejected by Scottish voters in 2014.

Scotland voted against independence by 55% to 45% in a 2014 referendum. But a majority of Scots also backed staying in the European Union in the subsequent 2016 Brexit vote, stoking demands by Scottish nationalists for a new independence vote after the UK as a whole voted to leave.

Scottish nationalist attempts to force a change to the United Kingdom’s constitution are a massive distraction while the government battles COVID-19, British Minister for the Cabinet Office Michael Gove said.

“At the moment, when we are prioritising the fight against the disease and also the need for economic recovery in due course, talking about changing the constitution and so on is just a massive distraction,” Gove told Sky News.

Gove said that Johnson, who had made himself minister for the union, was the best frontman for the keeping the United Kingdom together.