ian blackford
The Labour MP said there was an "irony" that other MPs were suspended for accusing Boris Johnson of lying.
His victory is a blow for Nicola Sturgeon.
His decision to quit means the SNP leader's influence over her troops at Westminster could now be diluted.
The shock move comes amid in-fighting among the party's MPs.
The PM was likened to Monty Python’s black knight, called a "lame duck" and told his own party "loathed" him.
"There's something wrong with a parliament where you're thrown out for pointing out someone's a liar rather than for lying."
"Honestly, there are eight-year-old children who wouldn't do that."
Nicola Sturgeon and Ian Blackford have been among those calling on Ferrier to stand down.
The SNP leader says she hopes Ferrier "will do the right thing" after taking a train from Glasgow to London and back with coronavirus.
Nicola Sturgeon's party won 48 of Scotland's 59 seats, ousting seven Tories and Lib Dem leader Jo Swinson.