The walkout was staged after Westminster Leader Ian Blackford was kicked out of the Commons, when he failed to comply with an order issued by the Speaker John Bercow.
Experts are calling the development unprecedented.
Central to the storm was the European Withdrawal Bill, which the SNP believes has been shoved down the throats of politicians on opposition benches. Blackford does not believe enough opportunity has been created for debate on the legislation.
The prevailing argument being that Scotland did not vote to leave the European Union and is now being forced to accept the terms put on the table by Prime Minister Theresa May.
Blackford had requested that there be a vote on the request for a private sitting in the Commons. Bercow told him that there could be a vote after the PMQ session.
Blackford and the SNP were having none of it though.
Some have called this a cheap publicity stunt, but Blackford insists that his party has now been forced to use parliamentary procedures to best effect, to advance the Scottish cause.