PETER Murrell is the most powerful SNP figure outside of the Holyrood and Westminster parliaments.

In truth, Murrell is much more influential than most of the party's MSPs and MPs, as well as almost all SNP ministers.

Murrell's wife, Nicola Sturgeon, and Deputy First Minister John Swinney are the only two figures with more sway.

As the SNP's chief executive during the party's 11 years in power, Murrell is in charge of the party's HQ, which is literally a stone's throw away from the Holyrood parliament.

READ MORE: Sturgeon's husband to be grilled by SNP over handling of Cambridge Analytica scandal

As chief executive, Murrell also heads the day to day running of the party.

Although little known to the public, Murrell presided over the SNP's three Scottish Parliament election wins, as well as its independence referendum campaign and the 2015 general election that saw the party win 56 of the 59 seats in Scotland.

However, Murrell has come under pressure following the loss of 21 of those seats in last year's general election and the handling of internal SNP difficulties such as the party's investigation into former minister Mark McDonald.