PR is good enough to elect many representatives; why not MPs?



Peter Facey of Unlock Democracy has made a very valid point on the Our Kingdom website:

 

“… the [Government’s] review [of voting systems] has not gone in the other direction, proposing to tear up the existing proportional voting systems in the UK (which are now used for all elections other than the ones for the House of Commons and local government in England and
Wales
).  The reason for that is that they have worked well, delivering balanced representative bodies in which pluralistic cross-party negotiation and scrutiny is the order of the day.” 

So why is no proportional system good enough, in the Government’s opinion, to elect MPs?