SNP
He has quit rather than face a vote of no confidence later this week.
The embattled first minister has quit after barely a year in the job.
The first minister's political future is hanging in the balance.
The SNP leader faces two votes of no confidence next week.
Scotland's embattled first minister faces a vote of no confidence next week.
Police Scotland said Peter Murrell, the former party chief executive, had been arrested for a second time earlier on Thursday.
Peter Murrell, the party's former chief executive, was first arrested in April last year and was released without charge.
The under-fire Speaker said he would allow one last week.
The SNP chief said his position was "untenable" following last night's Commons chaos.
The Commons Speaker was forced to apologise after chaotic scenes in parliament.