It is only week one of their new jobs and Scotland's rookie MPs have grabbed the headlines in the national as well as the Scottish press.

Just yesterday, we learned that they had been scolded for misbehaving. "Act like adults", the fresh batch of Nationalists were reportedly told by a colleague: 'It's a serious business."

The reprimand followed the unseemly scramble for seats on Monday, which had our elected representatives occupy the front row of the Opposition benches to ensure a good view of the election of the Speaker.

They were there early in the day and camped out for hours, presumably postponing the less pressing tasks of ending austerity or creating a fairer society.

Their high jinks could be put down to youth and inexperience; except that, behind the game of musical chairs, was one Pete Wishart, the veteran SNP member for Perth, who perhaps should have known better.

He was called "the biggest clown in the Parliament" by Labour's chief whip Rosie Winterton. Meanwhile, staff of the Nationalists' own chief whip, Mike Weir, ordered the team to stop taking selfies in the Commons chamber after Roger Mullin (MP in Gordon Brown's old Kirkcaldy and Cowdenbeath seat) posed at the Dispatch Box, aping the Prime Minister.

There have been other faux pas, such as clapping when told not to, and fluffing their oaths of allegiance to the Queen. Alex Salmond going off message after drinks on the Commons' terrace, and younger members commandeering Parliament's sports and social bar also made the news.

The SNP members have given Scotland a voice but not necessarily in the way Scots expected. Sometimes they resemble that handful of Scottish Socialists who, under Tommy Sheridan, stormed the Scottish Parliament and shook things up for five seconds but changed nothing.

Scotland's new MPs will soon settle down and the conscientious ones will get stuck into their constituency work and acclimatise themselves to the weekly commute.

As for bringing the weight of their numbers to bear in key votes, as another veteran, Stewart Hosie, promised, that might have been possible in a hung parliament, but is unlikely now that the Conservatives have an overall majority.

Despite the SNP's noisy claims to speak up for Scotland, they can only really hope to be heard if David Cameron loses that, admittedly slim, majority in a succession of by-elections over the course of the next five years.

Until (unless) that happens, the 56 will be much like Labour's 41 during the last parliament, collectively mute on the matters that affect their voters most: health, education, housing, crime, policing, which are all devolved.

How much did we hear about the achievements of Labour's Margaret Curran or Cathy Jamieson, both diligent MPs, when they were in the Commons? Their parliamentary record shows that they voted against university tuition fees and against a referendum on EU membership, among other things, but to no effect.

There was nothing wanting in the stridency of their voices when they held office in the Scottish Parliament, but in Westminster you need more than lusty lungs; your votes must count.

The SNP might be sending out a message of intent by appointing its MPs to cover all UK policy areas, but it will prove an empty gesture.

The problem for Scotland's new cohort is that they must make an impact in a way that will help the people of Scotland, while all the important decisions are being taken 400 miles away in Edinburgh.

Scottish ministers may find the Westminster intake adding to their in-trays, as the MPs grapple with policies outwith their control, but they can't get too involved. They are in government and otherwise preoccupied: declaring war on Scotland's landowners, defending their appalling handling of Scotland's schools, recalibrating A&E waiting targets.

Ironically, the issue that will galvanise the SNP MPs most is more powers for Holyrood, yet any extra concessions they win will further diminish what influence they have in Westminster.

Even on this matter, it is Nicola Sturgeon, an MSP, who will make the running. In her talks with the Prime Minister she will point to the 56 and talk about the tectonic plates moving in Scotland, and a mandate for change.

But Mr Cameron has a mandate, too. Not only has he recently won a general election but also, as he will no doubt keep reminding the First Minister, his Unionist argument won the independence referendum, convincingly, last September.

He has announced plans for extending devolution to the north of England. Can he afford to hand over to Holyrood much more than the Smith Commission recommended, and thus give the Scots a huge advantage over northern regions, many with bigger populations than Scotland?

Ms Sturgeon can sabre-rattle all she likes but over-estimating her party's clout in London won't strengthen her hand. She can encourage guerrilla tactics in the Palace of Westminster, and organise civil disobedience at home, but in the end it is only hard-headed negotiations between the Scottish Government and the hated Tories that will produce results.

The SNP's ploy to make mischief has been weakened on another front: Europe. There is change coming but the vast bulk of British public opinion is on the side of staying in.

This more or less takes Europe off the agenda for the Nationalists. It had been mooted that Ms Sturgeon's plan was to use anti-Europe England as a trigger for revisiting the separatist neverendum in pro-Europe Scotland.

But look what's happening in the south. George Osborne, the Chancellor, is sitting down with his German counterparts to thrash out solutions to their common grievances. Not much sign of Euroscepticism there.

Businesses are lining up, far quicker than they did in the Scottish referendum, to get behind Britain's continued European membership, with the CBI telling firms: "we're better off in the EU."

Ukip is in turmoil and losing the public's patience as its xenophobic raison d'etre fails to resonate in the popular consciousness.

And even Labour's likely next leader, Andy Burnham, has done a U-turn, conceding that voters have backed the Tory position, and saying that he now supports an in/out referendum on Europe.

If the SNP 56 had visions of championing a pan-party protest movement in the Commons over Europe they will be disappointed to find themselves very much within the consensus. They will have to seek divisions elsewhere to make their mark.

How they do that without risking their credibility as constructive politicians remains to be seen. Individual mavericks may carry on larking about and Mr Salmond will do his utmost to be visible, but to fulfil all the pledges to the Scottish people who propelled them south will require some skilled political judgment.

If they are found to be lacking that, the raised hopes of the half of Scotland that voted SNP are bound to be dashed, and some of those 56 will be one-parliament wonders.

It should be remembered, though, that Nationalist MPs are not motivated, as other MPs are, to make Britain stronger, but to break it apart. So those who are still there after the next General Election may regard that significant accomplishment as abject failure, having gone to Westminster in large numbers and still been unable to secure, and win, a second referendum on independence.