BBC News Published image copyrightPA Media image captionWillie Rennie had a karate lesson on The Meadows, Edinburgh while activists went door-to-door to point out SNP failures. Claims of "broken promises" by the SNP have become a key campaign tool for the Scottish Liberal Democrats. Activists in Edinburgh launched the party's "doorstep dossier" in a bid to win over disenchanted SNP voters. Party leader Willie Rennie said they were highlighting the SNP's "negative track-record" after 14 years in power. The SNP accused the Lib Dems of hypocrisy, having previously joined a coalition with the Conservatives at Westminster. The Scottish Liberal Democrats are hoping to stop the SNP gaining an overall majority in the Holyrood election on 6 May and want the parliament to put economic recovery first.