A MYSTERIOUS guerilla poster campaign has been launched in a bid to persuade SNP voters to help a Green Party land reform campaigner into Holyrood.

The notices, which have been spotted in Edinburgh, encourage pro-independence voters to back the SNP with their first vote and the Greens with their second ballot to get Andy Wightman, who is second on his party's list in Lothian, elected.

Activists have adapted the nationalists' logo to include branches and leaves and highlight Mr Wightman's success in advocating land reform - a totemic issue among many SNP supporters with some left frustrated that the Scottish Government was not as radical as it could have been in its last term.

The posters, which both the Scottish Greens and Mr Wightman deny knowing anything about, state that they have been produced by a group calling itself 'Maximise Yes', as smaller pro-independence parties attempt to persuade voters to ignore Nicola Sturgeon's 'Both Votes SNP' message.

Spotted this in Edinburgh today. Looks like @andywightman has a few fans. #SP16 pic.twitter.com/h6wCNTm26d — Stephen Paton (@stephenpaton134) April 21, 2016

There is no other evidence the 'Maximise Yes' organisation exists, with it having no apparent online presence and not being registered with the Electoral Commission.

The posters, which are likely to fall foul of election rules as they appear to have no information stating where they were produced or by whom, call for a "second vote to get land reform campaigner Andy Wightman elected instead of a unionist MSP" and state, above a picture of the candidate, "don't waste your votes."

While Alison Johnstone is almost certain to be re-elected for the Greens in Lothian, Mr Wightman faces a battle to enter the Scottish Parliament with his party only securing two MSPs in the region once before, in the 2003 'rainbow parliament' vote.

Holyrood's proportional electoral system means that if the SNP does as well as has been predicted consistently in opinion polls, it will almost sweep the board with First Past the Post seats putting it in line to win a majority on constituencies alone. As the more constituencies a party wins in a region the harder it is to get list MSPs elected, the SNP would be likely to pick up only a very small handful of top-up members nationwide if it is as successful as predicted on May 5.

The scenario has led some to argue that voting for the SNP twice will mean the regional vote is effectively wasted, and increase the chance of pro-UK parties winning the list seats instead. However, Ms Sturgeon has pleaded with her supporters not to play a "game of chance" with the electoral system, with the SNP pointing out that it depended on list MSPs for its first outright majority five years ago.

Mr Wightman said: "The first I knew of these posters was yesterday [Thursday] when a photo was published on social media. I don’t know who is responsible for them and neither does the Scottish Green Party."

Responding to the posters, a spokesman for the SNP said: "In less than two weeks' time voters will be asked to re-elect Nicola Sturgeon as their First Minister to keep Scotland moving forward to becoming a fairer, more prosperous country. The only way to achieve this is by using Both Votes SNP."