PGA Championship: Rory McIlroy, Jon Rahm, Lee Westwood & Sergio Garcia at Wentworth

Lee Westwood and Rory McIlroy were Europe team-mates at the 2021 Ryder Cup in Wisconsin

Europe's DP World Tour emerges into the limelight boasting a stellar field for one of its biggest events this week, but amid a backdrop of unprecedented rancour and uncertainty.

An outstanding line-up has been assembled for the prestigious BMW PGA Championship at Wentworth which starts on Thursday. US Open champion Matt Fitzpatrick is joined by the likes of Rory McIlroy, Jon Rahm and Viktor Hovland.

And, not so long ago the participation of Sergio Garcia, Patrick Reed and an up and coming young American such as Talor Gooch would also have been wildly celebrated by the European tour's hierarchy.

But these players are among 17 to have played on the breakaway LIV Tour. They are now turning up at Wentworth and to the golfing establishment they are rebels who are no longer welcome.

For McIlroy it is "hard to stomach" competing against players who have decided to take vast riches to play a rival circuit. However, the tour's boss Keith Pelley is unable to impose the sort of suspensions America's PGA Tour has put in place.

This tournament used to be known as the tour's "flagship" event. I'm not the first to note that this week it might be better termed the "battleship" version.

Indeed, two times major champion and LIV player Martin Kaymer is staying away because he does not want to be somewhere he feels unwelcome.

Then again, Ian Poulter, a golfer embroiled in legal action with both main tours, is among staunch LIV loyalists taking part.

Garcia - who is playing in this tournament for the first time since 2014 - and Lee Westwood and Graeme McDowell are other Ryder Cup team-mates of Fitzpatrick and McIlroy who could end up rubbing cold shoulders in the Wentworth locker room this week.

"I'm sure some guys will be tense about it [because] we're going to go out there and play," Garcia, who earlier this summer threatened to quit the tour, said at last week's LIV event near Boston.

"What I'm going to do is support the European tour and that's all I can do. Whoever doesn't like it, too bad for them."

Garcia, Westwood and Poulter flew through the night from the US to attend the DP World Tour's annual general meeting on Monday morning to ask questions about the strategic alliance, according to a report in the Daily Telegraph.

The build up to this week's event, which will continue with a lively looking players' meeting with Pelley on Tuesday before Wednesday's star-studded celebrity pro-am to which LIV players are not invited, has been as bitter as anything before a European tournament in living memory.

"The key to the anger felt by the ordinary, non-LIV members of the DP World Tour is that these guys who've taken the big money from LIV think they're entitled to come back and take the places of players who support our tour week-in, week-out," former Ryder Cup captain Paul McGinley told the Sunday Times.

"The LIV players don't turn up for €2 or €3m tournaments in the Czech Republic or Switzerland, but they come for the £6m tournament at Wentworth."

McGinley added: "This has led to a lot of resentment. Keith [Pelley] has spoken to virtually every one of our players. Not one wants the LIV guys in our tournaments."

But in keeping with the animosity that is abounding, another long-standing European figure, Gonzalo Fernandez-Castano, quickly hit back via the Spaniard's Twitter feed.

"Please don't speak on behalf of all the membership @mcginleygolf," stated the 41-year-old who has seven tour victories. "I have no problem whatsoever with the @LIVGolf players playing on the @DPWorldTour."

Others do, including US Open champion Fitzpatrick who voiced similar concerns to those of McIlroy about sharing a stage with players they feel should be bound by their choice to play elsewhere.

The feeling is these golfers sold out for Saudi Arabian millions. But they are still able to compete in this massive event and others on the European tour until a legal case is settled in February next year.

That hearing will determine whether Pelley can impose bans on those he considers to have defected from his tour to a rival set-up.

He will, at least, be buoyed by a sell-out of a different kind because all spectator tickets have been snapped up for the last three days of action on the West Course and vast galleries are expected for all four days.

It will be fascinating to see how fans react to players such as Poulter and Westwood who have always been crowd favourites at British events. There were stray boos at The Open in July but their reception was largely supportive.

No doubt the DP World Tour would hate to see the largest slice of the $8m (£6.96m) prize fund go into an already bulging back pocket of one of the LIV stars but, regardless, this is a huge week for the circuit.

Throughout this tumultuous year it has lived largely in the shadows. There have been a string of low key events since The Open with the average world ranking of the winner at a lowly 334.

This week it is big-time stuff and given the assembled field, it will be an event riddled with intrigue and argument. But, surely, sparkling golf as well.