In the following years Lamont became a fierce critic of the Major government. He is now regarded as a staunch euro-sceptic. In March 1995 he voted with the Labour party in a vote on Europe, and later that year he authored "Sovereign Britain" in which he envisaged Britain's withdrawal from the European Union, and was talked of as a potential leadership challenger to John Major; in the event it was John Redwood who challenged for the leadership. Lamont supported Redwood's campaign, which was managed by David Evans MP. He is the current vice president of the euro-sceptic Bruges Group.