Alex Salmond's Alba Party: who are they and do they pose a threat in the Scottish elections?

Alex Salmond will go head-to-head with Nicola Sturgeon in the Holyrood election on May 6, but will the Alba Party win any seats?

Alex Salmond's Alba Party: who are they and do they pose a threat in the Scottish elections?
Alex Salmond will go head-to-head with Nicola Sturgeon in the Holyrood election on May 6, but will the Alba Party win any seats?