Who could be the possible contenders to succeed Nicola Sturgeon as SNP leader and First Minister?

There appears to be no clear, obvious successor, in the way that Nicola Sturgeon stepped into the post vacated by Alex Salmond in 2014.

Instead, there is a number who may be considered possible contenders.

READ MORE: Nicola Sturgeon has resigned as First Minister

Angus Robertson: Likely to be an early favourite, should he decide to stand.

Glasgow Times: Angus Robertson MP poses for a photograph in Glasgow. Mr Robertson is SNP MP for Moray and SNP Westminster leader... Photograph by Colin Mearns.19 September 2016.

Current Cabinet secretary for the Constitution and has experience of Westminster and Holyrood.

A very experienced politician he has been dealing with the fallout from the supreme court decision against Holyrood holding a referendum without UK consent.

John Swinney: Deputy First Minister and the most experienced in terms of government roles of the possible contenders.

Glasgow Times:

Finance Secretary under Salmond then Sturgeon and number two to Sturgeon since 2014.

However, he has been the party's leader before, briefly, in the early days of devolution, and may not relish the opportunity to lead again.

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Humza Yousaf:

Glasgow Times:

 Glasgow Pollok MSP is considered by many to have been groomed as a potential leader. A long-time Nicola Sturgeon ally and rose through the ranks since becoming an MSP to top cabinet roles in justice and now health.

Kate Forbes: 

Glasgow Times:

Finance Secretary who proved her mettle when stepping in at a few hours' notice to deliver a budget when Derek Mackay resigned.

Since then has impressed the party with her handling of the finance brief.

Also has been considered to be a future leader but is currently away from Holyrood having recently given birth to her first child.

Neil Gray:

Glasgow Times:

Minister for Culture Europe and International Development. He has been in charge of the brief that sees Scotland maintaining links with the EU after Brexit and Ukrainian refugees coming to Scotland.

Could be a name when considering outsiders who may be interested in the top job.

There is also the possibility an MP could stand to be party leader and separate the roles of leader and First Minister.

The First Minister has to be chosen from Holyrood's 129 MSPs.