Siobhain Ann McDonagh (born 20 February 1960) is a politician in the United Kingdom, and Labour member of Parliament for Mitcham and Morden in London. She was first elected in 1997.
Her sister is Margaret McDonagh, Baroness McDonagh.
The most noteworthy feature of Siobhain's political record is her unswerving loyalty to Tony Blair's Labour Party. Despite some extremely controversial votes which saw large numbers of Labour MPs rebel against the government, such as foundation hospitals, university tuition fees, and the war in Iraq, Siobhain has almost without exception stuck rigidly to the party line (Siobhain McDonagh's voting record at 'The Public Whip').
