Angus Robertson has announced he is stepping down as SNP depute leader with immediate effect to pursue "new career opportunities".

Robertson, who was MP for Moray for 16 years, announced the decision in a letter to the party leadership telling Nicola Sturgeon he valued her "friendship, professional and personal support".

He also took to Twitter to thank colleagues and constituents.

He said: "Thanks to all colleagues and constituents over 17 years of public life.

"It's been a tremendous honour to serve as deputy of @NicolaSturgeon and help transform Scottish politics.

"Look forward to new opportunities but will always be there to help Scotland reach its full potential."

First Minister Nicola Sturgeon thanked the 46-year-old for his service.

She said: "Thank you @AngusRobertson - you have been an outstanding Deputy Leader of @theSNP and a huge support to me personally.

"You should be very proud of your enormous contribution to our Party's success. I wish you well and hope to see you back in frontline politics in the future."

Mr Robertson's decision comes eight months after losing his Westminster constituency in June's general election.