You know how it goes. There is an appeal for a boosted attendance and the public responds in good numbers. Then Carlisle United emerge from the tunnel at a packed Brunton Park, and freeze.

Big-crowd syndrome, we can call it. Myth or reality? Either way, it is a phenomenon that may well be up for inspection again in two days' time, with Portsmouth's visit likely to see one of the largest crowds of the season inside Carlisle's ground.

Keith Curle, for the umpteenth time this campaign, has called for people to fill the old stadium. Pompey, arguably League Two's biggest club, will certainly bring a four-figure travelling army.

With United back in promotion-chasing form, there is excitement at what may be in store in such a major fixture. But also you sense trepidation in some quarters.

Don't the Blues always fail to turn up on the big Brunton occasion? Don't they somehow seem more at ease when the Paddock is more sparsely populated, when the stands have a few more unoccupied seats, when the weight of public expectation is not quite so visible?

Those who subscribe to this theory have had some supporting evidence recently. Two weeks ago the visit of 14th-placed Blackpool brought a healthy 6,170 down Warwick Road. United were stuffed 4-1.

Three days later, the Tuesday night encounter with Doncaster was watched by 4,527. Naturally, the Blues ended the leaders' 10-match run with a superb 2-1 victory.

How do you explain this? Do United really shrivel in front of big crowds, where floating fans return, but thrive when a smaller and perhaps more concentrated representation of their fanbase is looking on?

Is it a fair conclusion, and a historical issue with the Cumbrians, or is it an urban myth?

The truth lies somewhere in between. Yes, there are some grounds for saying United get performance anxiety in front of big crowds. But the years also show they have been well capable of entertaining a large audience at times, too.

Perhaps the lack of consistent victories when the stadium is fullest explains the frustration when games like Blackpool come around. Grimsby, on January 2, was the same - a 3-1 defeat in front of 6,865.

This season's largest league crowd so far, though, was quite a different matter, and would anyone in the 7,333 attendance who watched the pinball drama of Carlisle 3 Hartlepool 2 on October 15 seriously argue that the Blues get stage fright as a rule?

That day it felt like the Blues, who won dramatically through Michael Raynes' header despite going down to 10 men, seemed to feed off the crowd's energy, not be intimidated by it.

So it can be done. Cup games are a harder measure, and while Carlisle were not particularly at the races when Everton's visit packed the Park last season, higher-league strength was always likely to assert itself that day even had they truly turned up. Rochdale, in this season's FA Cup, also fended off the risk of being upset victims.

The league, though, is where it truly counts - and history shows that United are not necessarily traditional line-fluffers.

Indeed, the glass-half-empty element may be surprised to learn that, of Carlisle's 20 highest post-war league attendances at Brunton Park, only five have seen defeats.

Four of those came in 1974/5, too, when United were upstarts in the old First Division, and losing the odd game was to be reasonably expected.

The only other home setback in that top-20 list was inflicted by Blackburn, in 1966/7, in front of 17,523 in Division Two.

Otherwise, Carlisle totted up the wins and draws. The most recent game to feature on that roll-call was Leeds' visit in 2007: a storming 3-1 win for John Ward's team when the Blues certainly played to the gallery in the best possible way.

That November afternoon saw 16,668 royally entertained. United's comeback saw the stadium at its noisiest for many years.

Certain other big days have brought similar success. Of their top 20 league crowds, seven saw wins, and eight draws.

Not a completely emphatic record, perhaps. But certainly not evidence that the Blues are shrinking violets, either.

Famous examples of Carlisle turning up in a strong way are there. How about Mansfield, on the final day of 1964/5, when a 3-0 win clinched the title in front of 18,524?

Or the 1-0 downing of Sunderland in 1973/4's Division Two promotion push, where 19,692 enjoyed Chris Balderstone's penalty winner?

This certainly contests the idea that the Blues have a long-established aversion to crowds.

More recent evidence, though, does not completely follow this positive pattern, and United failing to deliver in front of lots of people is not a complete illusion either.

This is perhaps where some of the fatalism comes from. Under the current ownership regime, which started in 2008, a look at Carlisle's biggest home crowds does not, in fact, yield lots of confidence-boosting wins.

Indeed, of the previous nine campaigns, the highest individual home league crowd in each term has only seen one victory.

That was in 2011/12, when 7,721 saw Francois Zoko inspire United to victory against Sheffield United.

Other times, results have been mixed. Last season, for example, we had the memorable return to Brunton Park after the floods. The 7,461 who attended had to make do with a rather anti-climactic 1-1 draw against relegation-bound York.

Before that, 8,105 saw the Blues lose a three-goal lead to Hartlepool to draw 3-3. The previous season, 7,934 watched Preston steal a 1-0 win.

Even North End under Graham Westley managed to leave a busy Brunton Park with a point the year before. In 2010/11, a ticket promotion involving sponsor Eddie Stobart swelled the crowd for Rochdale's visit, but again, a draw was the best the Blues got.

Leeds' other league visits after that 2007 drama again brought the biggest crowds of Brunton Park seasons - but with different outcomes. In 2008/9 and 2009/10, the men from Elland Road won both times, in front of 12,148 and 8,728 respectively.

These findings will feed the more pessimistic views. It is granted, though, that this is just one way of handpicking statistics to judge a trend. Plenty of different variables are always at play, such as form, status, opposition, injuries, exactly what is at stake, and all the other usuals.

Maybe, then, it's best to approach Pompey on Saturday in the same way as usual - hoping for the best, guarding against the worst, but certainly cheering when needed and still keeping faith that the 12th man can be a help at Brunton Park after all, not a hindrance.