The Government today accused Iran of a "long line of slurs" amid claims four people with links to Britain had been arrested.
Iran claimed it had arrested four people suspected to be members of a British-linked terror cell blamed for at least five killings since 2008.
But a Foreign and Commonwealth Office spokeswoman dismissed the report as "baseless".
She said: "The UK does not support or encourage terrorist activity in Iran, or anywhere else in the world, and this claim will be seen as what it is: another in a long line of slurs against the United Kingdom from the government of Iran."Reuse content