From his demeanour, you would never know that anything was wrong around Jackie McNamara, or that there was trouble or anxiety in the air.

The Dundee United manager appears permanently unperturbed, seemingly detached from the noise and the fury. Amid an earthquake, with bits of masonry falling around him, you can almost imagine McNamara leaning against a post, looking up in fascination.

The look must be deceiving. It is unlikely that this 41 year old, unlike any other manager in Britain, does not feel the heat or the barbed criticism. And plenty of the latter is coming McNamara’s way these days.

Including last season’s abrupt disintegration, Dundee United’s form has lolled between flimsy and rotten for some time now. The current grim statistics, after last Saturday’s 0-4 calamity at Hamilton Academical, reveal five wins in 23 competitive matches.

There is no other way of putting it: this is approaching sacking terrain.

The way the wheels have flown off McNamara and Dundee United’s bandwagon in recent times has been shocking to behold. And the Tannadice faithful, either at games or on social media, have not sat back and taken it all phlegmatically.

No manager can live on his past – excepting exceptional circumstances, football doesn’t really allow that. In the 18 months following McNamara’s appointment as Dundee United manager in January 2013 there seemed a momentum and quite a style about United’s play. Tannadice was brimming with enthusiasm.

All of that memory, though, is receding alarmingly. Everyone knows what happened at the club, with key talents like Ryan Gauld, Stuart Armstrong and Gary Mackay-Steven being sold. As a selling club United’s homegrown progress was virtually stopped in its tracks.

That being said, a fair way to judge the progress or not of Jackie McNamara is to critically assess his rebuilding of his team. McNamara inherited a fine squad, but it has gone. The question now is, how capable is he in building his own team? This is, after all, what a football manager does.

The jury remains unconvinced about this. A host of new signings – Simon Murray, Darko Bodul, Luis Zwick, Mark Durnan, Coll Donaldson and more – have been added over the summer to other McNamara purchases of recent times.

It can now be said emphatically: this is McNamara’s Dundee United and no-one else’s. He is convinced of the quality he has assembled but, if results don’t turn soon, either the players will have failed or he will have failed. Either way, the upshot will be the same.

Some Dundee United fans are already calling for McNamara’s head but, four weeks into the new season, and despite that horrific episode at Hamilton, this seems harsh. United were unlucky not to beat a lauded Dundee side last week, having been 2-0 up. This new Tannadice team still has plenty time in which to come good.

But what is alarming for many United supporters is the sheer lack of direction and conviction in their team’s play, borne out by five months of results, and stemming, they claim, from their manager’s leadership.

The next few weeks could have a decisive effect on Dundee United’s season. Celtic are at Tannadice on Saturday but thereafter United’s fixture-list looks less than daunting: Ross County, Kilmarnock and Caley Thistle all come in quick succession in the Ladbrokes Premiership.

There will be little room for compassion towards McNamara if his team cannot accumulate a healthy crop of points from these games. United, by every measure, should have the beating of these opponents.

No-one can forget the work of McNamara in his two opening full seasons at the club. To finish fourth and reach a Scottish Cup final, and then fifth and reach a League Cup final, is satisfying going. Little wonder, amid all this, McNamara received many plaudits.

But the harsh truth is, it will count for little in time. Football lives very much in the here and now. A manager is judged by progress, not by giddy events of the past.

There are wider issues causing dismay at Dundee United, some of them relating to chairman, Stephen Thompson, and to the suspension of Stevie Campbell, the club’s director of youth. The Arab Trust, a respected body of United fans, has also aired repeated grievances over club-supporter relations and other matters.

But the catalyst for everything is a good manager. Jackie McNamara has been that. He needs to show again, with his own team this time, that he can steer United to further success.

To that end, the month of September looms ominously.