Downing Street has issued an apology after the Isle of Man was wrongly included on a map of the UK posted on its Twitter page on Monday.
The tweet, made ahead of the Scottish Independence vote, said: "By staying united we have much more to gain."
The Manx government replied: "Please could this map be corrected the Isle of Man is not part of the United Kingdom."
A spokesperson for Number 10 said: "We apologise for the error and will ensure it doesn't happen again."
He added that the "graphic has been amended for any future digital activity".
The Isle of Man is a self-governing Crown Dependency like the Channel Islands of Jersey and Guernsey.
According to the Manx government the Isle of Man is not, and never has been, part of the United Kingdom, nor is it part of the European Union.
It is not represented at Westminster or Brussels and is a self-governing Crown Dependency with its own parliament, government and laws.
The UK government on behalf of the Crown, is ultimately responsible for its international relations.