The surest sign of consistent quality in European club rugby is visible just above the heart. Those four little gold stars woven into Leinster’s jersey might not immediately catch everyone’s eye but if you know, you know. Each of them denotes a European Cup title and adding another on Saturday will gain the Irish province entry to the most rarefied of clubs.

Currently the French thoroughbreds of Stade Toulousain are the sole occupants of this elite five-star enclosure, courtesy of victory over La Rochelle in last year’s final. Next up, after Leinster, are Toulon and Saracens with three while Munster, Leicester and Wasps are the only other teams to have raised the trophy more than once. In the past 20 years only one side from outside that magnificent seven – Exeter – have conquered Europe.

Leinster’s recent form strongly suggests they could draw level with Toulouse this weekend. Of course, Ronan O’Gara’s La Rochelle beat them in last year’s semi-final and nothing can be remotely guaranteed. But should Leo Cullen’s side prevail in Marseille it would be the fifth time in 14 seasons the trophy has ended up in Dublin. Considering the opposition involved over that period, that would be some achievement.

Which inevitably kickstarts one of those subjective pub arguments. Are Leinster on the verge of becoming the greatest European club side of the pro era? There will be plenty of spluttering in France but, increasingly, there is a strong case to be made. Not just in terms of trophies but the manner in which they are increasingly getting the job done.

It is all very well saying the English league leaders, Leicester, started slowly in the

quarter-final at Welford Road or that Toulouse were below their best in the semi. That is what top sides do: even decent opponents are made to look moderate. And when you looked at the scoreboard at the end of both of those matches, against sides containing some top-notch individuals, the aggregate was 63-31.

At which point another familiar cry goes up: they should be good, they’re Ireland in disguise. Which is mostly true in terms of personnel. But, conversely, what if it is Leinster’s excellence that has filtered upwards to Ireland’s national team rather than vice versa? And either way, is that not the perfect yardstick by which to judge whether a club (or provincial) side truly are the real deal?

So let’s proceed accordingly. Two of the greatest European champions in terms of the quality of their title-winning performances were the Brive side of 1997 and Leicester in 2001. But while Brive were simply scintillating in Cardiff, carving open the Tigers to win 28-9, they did not necessarily boast a team full of internationals. Their flying winger Sébastien Carrat was a French national sprinter, for example, but he never won a cap for Les Bleus.

Hugo Keenan touches down for a try during the January rout of Bath.
Hugo Keenan touches down for a try during the January rout of Bath. Photograph: Andrew Couldridge/Action Images/Reuters

Leicester’s forwards, however, were pretty much the England pack in disguise, with the talented Pat Howard, Geordan Murphy and Austin Healey outside them. Their 34-30 victory over Stade Français in Paris was also as compelling a finale as any in the tournament’s history. There is only one snag: having retained the trophy the following year they have drawn a Champions Cup blank over the past 20 years.

Despite the fabled deeds of Munster and the famous knockout acumen of Wasps, then, the all-time shortlist arguably has to be whittled down to four: Toulouse, Leinster, Toulon and Saracens. Toulon were as star-dusted a side as the competition has ever known and no other team have won three consecutive titles. The most eye catching, without doubt, was their 23-6 humbling of Saracens in 2014 when Matt Giteau and Juan Smith scored the tries, Jonny Wilkinson kicked the goals and Steffon Armitage – remember him? – claimed the man-of-the-match award.

Sarries, too, had some extra-special moments, not least in Newcastle in 2019 when they overpowered Leinster. Maybe there would have been more titles had the salary cap saga not intervened. Toulouse, meanwhile, stand out for their longevity and sustained pedigree, although two of their five final wins were achieved in extra-time and the combined winning margins of the other three were a modest 12 points. Arguably the final in which they played some of their most compelling rugby was in 2004 against Wasps at Twickenham, which they lost courtesy of Clément Poitrenaud’s late howler.

Jonny Wilkinson lifts the trophy after Toulon’s 2014 triumph.
Jonny Wilkinson lifts the trophy for Toulon’s star-studded side in 2014. Photograph: Tom Jenkins/The Guardian

For my euros, though, the two most striking all-round European sides – capable of playing in a variety of ways, with power and panache and with sustained Test-class excellence – have been Toulon and the modern-day Leinster. Nothing, it should be stressed once again, is yet settled but the Dubliners are still improving. They can scrummage with the best of them and their tighthead can throw 25-metre passes in open play. Their back row never take a step backwards and neither do their midfield. They possess a high-level kicking game – out of hand and off the tee – and their half-backs are tactically outstanding. When Leinster really up the tempo there is a savage beauty to their clinical execution.

So who would win if the Toulon of 2014 played the Leinster of 2022? Shifting the tickets would not be a problem, that’s for sure. Never mind Wilkinson and Giteau, what about Bakkies Botha, Carl Hayman, Jean-Martín Fernández Lobbe and Bryan Habana? With Martin Castrogiovanni, Ali Williams and Mathieu Bastareaud as back-up? Perhaps best not to bet the Monte Carlo-based yacht on an Irish romp.

But should Leinster win well on Saturday the “ultimate” question can legitimately be raised. Right now Johnny Sexton, Jamison Gibson-Park, Tadhg Furlong, Josh van der Flier, Robbie Henshaw and the rest of their squad of hungry internationals are displaying a rhythm and certainty exhibited by only the very best. A fifth gold star on their jerseys this weekend would truly cement their lofty status.