London transport staff have been warned after anti-vaccine posters with razor blades on the back were found, a union has said.
The Rail, Maritime and Transport (RMT) union said they had been put up in Tube and rail stations across the capital.
It called for action against those responsible for the posters, which read, ‘Masks Don’t Work’.
Transport for London said it was not aware of any incidents of this nature but had given advice to it workers.
A similar poster was found on a crossing in Cardiff where a woman was injured while trying to remove it.
The RMT has formally raised the issue with Transport for London and said warning bulletins highlighting the danger of injury have now been issued to staff.
General secretary Mick Lynch said: “Any anti-vax conspiracy theorist resorting to this disgusting practice of lacing their propaganda with razor blades needs to know that they will face criminal prosecution and the highest possible sentences.
“As far as RMT is concerned they should be locked up for a long time. We would expect the police and the courts to take the hardest possible line.”
Transport for London (TfL) said it was not aware of any incidents of this nature involving razor blades taking place on its network.
A TfL spokesperson said: “We act urgently to remove unauthorised materials from our network, such as posters, including those relating to the pandemic.
“The safety of our customers and colleagues is paramount and we have issued guidance to our staff on how to remove them safely after reports of instances outside of our network of razor blades being attached to the back of such materials.
“None have been detected on our network and there have been very few instances of unauthorised adverts and materials relating to the pandemic.”