In 2005 he stood for the Westminster constituency of Edinburgh North and Leith, coming second to Labour's Mark Lazarowicz and securing a swing of 8.3 per cent from Labour to Lib Dem. In November 2005 he again sought election to the city council, standing in another by-election in Murrayfield, and again came second. In the 2007 Scottish Parliament elections in the smaller Scottish constituency of Edinburgh North and Leith, and again secured a large swing from Labour but still finished in second place.
Edinburgh West
In 2009, John Barrett, the Liberal Democrat MP for Edinburgh West announced his retirement, prompting a nomination fight. Crockart stood, as did city council housing leader Paul Edie, former Borders MSP Euan Robson and former Edinburgh CentralScottish Parliament candidate Siobhan Mathers. Crockart defeated Edie by 77 votes to 57. He retained the seat for the party in the 2010 general election with an 8.2 per cent majority, despite suffering a large swing to the Labour Party of 11.4.
Member of Parliament
The result from the 2010 election produced a situation whereby no one party had a majority in the House of Commons and so a coalition agreement was drawn up between the Conservatives and the Liberal Democrats. As a result, Crockart, in his first term as an MP, was now sitting on the Government benches as opposed to the opposition ones. Speaking about the agreement, Crockart claimed that this was a "bold and ambitious agreement" that would bring "positive change to Edinburgh". Crockart was appointed the Parliamentary Private Secretary to the Scottish Secretary Michael Moore. During the 2015 general election campaign, Crockart criticised the Scottish National Party for issuing campaign letters referring to him as the "retiring MP".
Resignation as PPS
On 9 December 2010, Crockart resigned as Michael Moore's PPS to vote against the government's proposed rise in tuition fees. In his resignation letter, he told party chief whipAlistair Carmichael that the rise in potential student debt will "seriously impact on people's choices". He went on to say, "this is especially true for those students from poorer backgrounds, many of whom have no role models in their schools or families to demonstrate to them the benefits which can accrue from a university education." Crockart had hit the headlines prior to the vote after being the victim of an impersonator who managed to convince show producers on the BBC Radio 4 programme The World at One that he was the Edinburgh West MP. The impersonator told presenter James Robbins, "I will be voting 100 per cent against. I'm not going to be pushed out. Resigning probably will be the only option." The Liberal Democrat press office pointed out the error as the impersonator had an English accent whereas Mike Crockart has a "distinctly Scottish burr". Of the error the BBC said, "The usual pre-broadcast questions were asked of the person concerned, who maintained throughout that he was Mr Crockart and appeared credible....Once the mistake was realised, steps were taken immediately to rectify the error and to ensure it was not repeated."