Downing Street has attempted to have vials of the Oxford University Covid vaccine labelled with the Union flag.
No. 10 asked a taskforce set up to fight calls for Scottish independence to work on having injections kits covered with the flag, the HuffPost UK has revealed.
It also asked the unit focusing on developing the vaccine to insist manufacturers use the UK flag.
No. 10 said there are no plans to use the flag on doses but fell short of denying claims that health secretary Matt Hancock and business secretary Alok Sharma had been promoting the idea.
A government spokesperson said: “Manufacturing for some of the leading potential vaccines is already underway so they can be rolled out quickly if approved.
“Manufacturers are well-versed in the best way to package products like this.”
It came as Nicola Sturgeon told the BBC she would seek a second independence referendum “in the earlier part” of the next Scottish parliament.
The SNP are on course to firmly win the 2021 Holyrood elections and argue a landslide victory should warrant a second independence vote, which Westminster is strongly rejecting.
It is believed Boris Johnson’s advisers want to highlight the British success of the vaccine in a bid to strengthen support for the Union.
One Whitehall official told HuffPost UK there had been an intensification in recent months on shoring up support for the Union.
“There has been a renewed interest on the impact of policy decisions on the union, and ensuring it is in no way detrimental to the devolved nations,” she said.
“It is something we have to constantly be mindful of. They are trying hard to keep the union intact.”
Others inside Westminster say promoting the vaccine as a British treatment would instil public confidence in it and help ward off the anti-vaxxer movement.