Bosses at three of the UK's largest employers have threatened legal action on Vote Leave after the Brexiteers included the firms' corporate logos in flyers.
The chief executives of Unilever, Airbus and General Electric wrote a letter to the Leave camp yesterday, claiming that the letters constituted misrepresentation, as all three strongly back a Remain vote.
In their letter, the trio claimed their companies had been used for "propaganda" purposes to imply support for an exit.
"That is not our position; on the contrary, we believe that - for jobs and investment - Britain is better off in Europe, and we have signed letters and made statements in the media to that effect," they said.
"We consider the misrepresentation of our businesses and the use of our company names and logos to be both highly misleading to British voters, and an act of bad faith towards our companies on the part of your campaign."
The companies have asked the Leave camp to destroy any leaflets that have not already been distributed, and copied the letter to the Electoral Commission.
"Should this reoccur, we shall take whatever further action - including pursuing legal means - we deem necessary, and without further notice," they add.
A spokesman for Vote Leave declined to comment.