<sod >" In response, Ms Sturgeon expressed her "immense gratitude"Â  to Mr Robertson.< eod>< sod > " Adding that he was "tremendously honoured" to serve as deputy leader and "immensely proud" of what the SNP has achieved, Mr Robertson said he would continue to "support public policy development in Scotland" as an advisory board member of the Scottish Policy Foundation. In response, Ms Sturgeon expressed her "immense gratitude"Â  to Mr Robertson.< eod>