If the 20 MPs are prosecuted and found guilty there would have to be byelections in all of those seats. The government’s majority in the HoC is *less* than 20, thus they wouldn’t have been able to form a majority government in 2015 without those 20 MPs, who, potentially, gained their seat through illegal means.
The CPS is due to make its decision in about 8 weeks time. We shall see.
I read that the party machine are already throwing their own elected candidates under the bus. What else did these deeply naive people expect?