He was first elected to Parliament in 2001 and in his first term was the SNP Spokesperson on Trade and Industry and Work and Pensions, as well as being a member of the Scottish Affairs Select Committee (2001–05).
Since 2005 Mike Weir has been the SNP Westminster Spokesperson on Business and Enterprise (which includes energy) and the Environment.
He has been an outspoken opponent of nuclear power and has pursued a relentless campaign on the future of the Post Office network.
Mike Weir sat on the Business, Innovation and Skills Select Committee (2005–09) and was a member of the Chairmen's Panel/Panel of Chairs from (2005–10).
Weir has championed issues relating to energy including calling for "social tariffs" for poorer utility customers and opposing pre-payment meters[1] As postal affairs spokesperson Weir led SNP opposition to privatisation of the Royal Mail[2] He raised the issue of local driving test centre closures at Westminster[3] Mike Weir served as the SNP's Chief Whip in the House of Commons during the 2015-17 Parliament.