The coalition government has warned Scottish hauliers they could face significant charges when using the roads in England and Wales if their country successfully achieves independence from the UK.
Plans to separate Scotland from the rest of the UK appear to be gathering pace, but this could be bad news for logistics firms, which might be forced to fork out up to £1,000 a year just to make deliveries south of the border.
The government is planning to charge foreign truckers when they enter Britain, with the money being used for general road maintenance.
UK businesses will have the fees offset against other road taxes - a move that the authorities hope will help local firms compete with European companies that benefit from lower fuel prices on the continent.
However, if Scotland does break away, its hauliers could be treated the same way as foreign truckers.
David Mundell, a Scotland office minister, said: "Every time we look under the bonnet of independence we find something else problematic."
It is not just road transport firms that are worried about the implications of going it alone. In May, Scottish train drivers voted unanimously against the Scottish National Party's independence campaign.