It's fair to say Paul Pogba didn't look too thrilled when he arrived at Manchester Airport on Sunday afternoon.

The only member of the Manchester United party not to be wearing a club blazer, Pogba glared and scowled as he dodged the photographers and holidaymaker crowds to reach the terminal.

Of course it might have been the prospect of a gruelling 17-hour flight to Perth, for the first leg of United's pre-season tour that will take them to Australia, Singapore and China.

Paul Pogba didn't look too happy as Manchester United departed for their pre-season tour

The French midfielder clashed regularly with United's former manager Jose Mourinho

Ed Woodward tacitly backed Pogba - but now that trust has been thrown back at them

More likely, his mind was questioning quite why he was reporting for duty with a club he is actively seeking to leave this summer.

Pogba has kept himself away from the club's official photographers, with images circulated by United's social media accounts rarely showing him in the foreground.

It's not exactly a secret that his agent, Mino Raiola, has been instructed to find Pogba a fresh challenge. He has said as much, after the player himself said indicated likewise while on a summer promotional tour of Asia.

Really, Pogba was quite happy passing his summer in New York, where he posted an Instagram video of himself running through Central Park last week, and waiting for the call from Real Madrid or Juventus.

Instead, he is off to the other side of the world, going through pre-season fitness work and playing friendlies for a team he hopes to be leaving, three years after re-joining.

There were doubts he would even report back to United's Carrington training base on Sunday morning ahead of the flight to Australia, a suggestion perpetuated by Raiola last week.

Pogba pictured in action against Cardiff in May - it could be his final appearance for United

Pogba made clear that he wanted to leave United this summer during a promotional tour

Pogba, on Saturday, posted videos on Instagram of him training while on a break in New York

United delayed the announcement of their tour squad as a result but, in the end, Pogba turned up in a chauffeur-driven Mercedes people carrier just in time.

It was these little things that created the cracks in Pogba's relationship with former manager Jose Mourinho, sacked in December last year after just seven wins in the first 17 Premier League games of the season.

Mourinho was infuriated, for example, that Pogba arranged to travel back to Manchester in a chauffeur-driven Rolls-Royce instead of on the team coach following September's 2-0 win at Burnley.

That came around the same time Mourinho stripped Pogba of the United vice-captaincy, humiliating him in front of his team-mates.

There was also a row over an Instagram video the Frenchman filmed in the stands during United's Carabao Cup defeat to Derby County and the infamous argument in training which happened right in front of the Sky Sports cameras.

A few months after he left United, Mourinho described Pogba as 'His Excellency' in a dig at his diva-like actions, adding that he feared the sack if he did too much to upset the Frenchman. Well, look what happened in the end.

Pogba and Mourinho fell out for a number of reasons as two big personalities clashed

An argument between the pair in training last season was captured by the Sky Sports cameras

Mourinho wasn't impressed that Pogba was chauffeured back from an away game at Burnley

After their disastrous opening to the season, with schisms appearing in the dressing room and an atmosphere of negativity pervading everything they did, United effectively had to choose between Mourinho and Pogba.

Executive vice-chairman Ed Woodward decided to dispense with Mourinho, rather than backing his manager to turn things around and trying to offload Pogba in the January window.

The fact that Pogba cost the club a world record £89million when he returned to United, shortly after Mourinho's appointment, in the summer of 2016, and is their most marketable asset, seemed to guide Woodward's thinking.

And in so doing, Woodward and the United hierarchy tacitly said that one player can be bigger than the club and can influence the dressing room as much as he likes.

He can create cliques, influence younger players and undermine the manager while also not producing on the field.

It certainly wouldn't have happened under Sir Alex Ferguson, who enshrined that no player is bigger than the club as a pillar of his management philosophy.

Mourinho was furious when Pogba posted Instagram videos during United's defeat by Derby

Pogba's relationship with Solskjaer is better, but it hasn't stopped him seeking an exit

UNITED'S TOURING SQUAD Goalkeepers: De Gea, Grant, J. Pereira, Sergio Romero Defenders: Bailly, Dalot, Jones, Lindelof, Rojo, Shaw, Smalling, Tuanzebe, Wan-Bissaka, Young Midfielders: A. Pereira, Chong, Garner, Gomes, James, Lingard, Matic, McTominay, Pogba, Mata Forwards: Greenwood, Lukaku, Martial, Rashford Advertisement

Now, with Pogba explicitly saying he wants to leave Old Trafford despite there being two years remaining on his £290,000-a-week contract, it really does look like a poor decision.

They backed Pogba by getting rid of Mourinho and bringing in Ole Gunnar Solskjaer, but have now seen that loyalty and trust in him thrown back in their faces.

Maybe Mourinho was right after all in identifying that Pogba was actually the cause of many of United's early-season problems and United lanced the wrong boil.

That isn't to say that Mourinho shouldn't have gone too. United's form was dreadful and his negative tactics were attracting criticism.

United initially enjoyed a resurgence under Solskjaer, with the memorable comeback win against Paris Saint-Germain in the Champions League securing the job full-time, but then collapsed spectacularly towards the end of the season.

Being outplayed by Barcelona is one thing; losing 4-0 at Everton and 2-0 at home to relegated Cardiff quite another.

Real Madrid manager Zinedine Zidane is hoping to lure the midfielder to the Bernabeu

Juventus are also keen to bring Pogba back to Turin - where he spent four seasons with them

Pogba's form improved dramatically after Mourinho's departure, as though the gloom had suddenly lifted and he had been liberated on the field, but it wouldn't last.

In the final few matches of the season, he was as anonymous as he'd been before. As United slumped to a sixth-place finish and Europa League football, it was clear he wanted out.

His relationship with Solskjaer is sound, a contrast to his problems with Mourinho, but that won't be enough for a World Cup winner who craves more medals and glory and clearly doesn't fancy Thursday nights against the likes of Zorya Luhansk, Mlada Boleslav and Lugano.

Pogba believes he should be playing at the business end of the Champions League - which he would be at Real or Juve - while earning £500,000 a week.

He will argue forcibly that he doesn't belong in the Europa League and that United cannot match his ambitions. And that this is ample justification to leave.

United have only seen glimpses of Pogba's best form during his three seasons at Old Trafford

Pogba helped United win the Europa League in 2017, but he doesn't fancy playing in the competition again next season

But questions remain over whether Juventus can afford to buy him back - United will want a handsome return on their £89m investment, perhaps as much as £150m - or afford his wages.

Real have spent huge already this summer on the orders of Zinedine Zidane, with £150m paid for Eden Hazard, £62m for Luka Jovic, and more on defenders Ferland Mendy and Ederson Militao.

Further spending remains likely, but will Real stump up for the midfielder and be prepared to meet his wage demands?

United will have to dig in their heels to save face after doing so much to back Pogba last winter. The official stance is that he is going nowhere.

But it's highly likely Pogba won't be lining up in United colours by the time they open their Premier League season against Chelsea on Sunday, August 11.

In the meantime, he'll have to suck it up and play for them in these pre-season outposts as the club reflect on a player vs manager gamble that paid off initially but has now well and truly backfired.