Marooned somewhere they don't want to be, the iron discipline of the SNP, the Bolsheviks of Westminster, is under strain for the first time.

Disillusionment is creeping into a Parliamentary force initially displaying a unity Lenin or Stalin would've admired, as the novelty of working in London wears off for those with their heart in Edinburgh.

A number of the party's MPs are grumbling the devolution of financial powers to their homeland and no second independence referendum on the horizon is sucking the life out of their role.

Scotland's Nationalists are discovering also a Conservative majority in the House of Commons postponed the revolution promised back in May. Like Labour and every other party it's powerless without Tory rebels and hated alliances.

"You can roughly split us 50-50 between those who make the most of it and those who absolutely hate it," says an SNP MP elected in last May's Nationalist tsunami when the party won 56 of Scotland's 59 seats.

"I love it and there are many ways to make the case for Scotland in the chamber, committees, signing Early Day Motions and all the rest of it.

"Others, and I concede this, think Westminster's not for them and you can see their enthusiasm waning."

The Cry Freedom brigade's occupation of an office block on the edge of the Parliamentary estate near Whitehall's Red Lion pub, Nats renaming the building Caledonia House, a bit of England that is forever Scotland unless independence is delivered, reinforced a cultivated separatism.

Until waning enthusiasm, the only discernible split in the Westminster block was between Nationalist 'wets' drinking in the Sports and Social (although in recent weeks noticeably more of the SNP are slaking thirsts in the more ecumenical Strangers' Bar) and Nat 'drys' preferring Westminster’s restaurants.

But as the gloss wears off the initials M and P the danger for the party's leadership is disenchantment may result in MPs veering off message.

Members of the SNP in the Westminster Parliament it wishes to vacate admit they are under a heavy obligation to avoid embarrassing First Minister Nicola Sturgeon in the Edinburgh Parliament it yearns to rule a separate Scotland.

With the Scottish elections in May, the propaganda volume will be turned up and another resounding victory in Edinburgh would paradoxically emphasise their irrelevance in Westminster, fuelling that disaffection.

MPs in rival parties detect the growing disappointment though many remain sneaky admirers and quips about the SNP moving as a herd, the clip-clop of 50 or so pairs of shoes signalling the SNP's arrival, are laced with envy when the Tories are splitting over Europe and Labour's bitterly divided on Jeremy Corbyn.

Barrow Labour MP John Woodcock compared the uniformity of the SNP with more than a hint of admiration to the common purpose of his own party in Westminster in Tony Blair's heyday.

"We laugh at the robots," says an English Tory. "But our party and Labour are becoming beyond a joke. The SNP are all about discipline. With us it is ill-discipline."

The entrenched dominance of the SNP as Scotland's political voice remains unchallenged when two MPs denied the whip during inquiries into alleged misdemeanours, Michelle Thomson and Natalie McGarry, make suspended Nationalists the second strongest grouping in country where Labour, the Libs and Cons boast a single MP each.

Westminster leader Angus Robertson regularly gives Jeremy Corbyn a lesson in rapier thrusts and how to discomfort David Cameron with punchy questions. MPs such as Glasgow South West’s Chris Stephens, secretary of the SNP Trade Union Group, know what they’re talking about when opening their mouth. And Mhairi Black, at 21 the Baby of the Commons, represents a healthy contempt for Parliament’s potentially neutering clubby flummery.

Yet the lost tribe wandering Westminster with seemingly little to do except scratch grievances, real or invented, is spreading out and stragglers are emerging as cohesion weakens.

Sturgeon's worst nightmare would be Scots going native in the Parliament she wants to dump.

PHOTO: John Stillwell/PA Wire