The battle for the glorious past will be fought in the inglorious present. And it will be fought with heavily edited Twitter videos. Early last week Real Madrid TV released what can only be described as an attack video, aimed at the former La Liga referee José María Enriquez Negreira. If this seems a little extreme, it is worth noting this was in fact a follow-up, sequel to Real Madrid TV’s previous attack video aimed at referee Carlos Clos Gómez, now head of La Liga VAR.

There have been grander, starrier, more knife-edge meetings between Barcelona and Real Madrid. But not many have been more strangely pitched than Sunday night’s clásico at the Camp Nou, or more obviously fraught with angst, mudslinging and paranoia.

The game itself will either decide the title race or inject a little late-breaking life. Defeat would cut Barcelona’s lead at the top to six points with 12 matches to go, which still looks like a lot of points. The gap from Barcelona to Atlético Madrid in third place was a muscular 17 going into this weekend. Squint and it could almost be the grand old days of the global duopoly, when the bloom of the Messi-Ronaldo years made this fixture football’s grandest single event.

But this isn’t quite that. Instead this is a fixture that will be played out to the sound of the recent past being angrily divvied up. The European Super League fiasco had seemed to heal the old wounds in the name of pursuing common interests, with reports of Joan Laporta and Florentino Pérez being seen regularly taking dinner together. The latest from Barcelona is that Laporta is considering cancelling the traditional pre-clásico lunch. Instead La Liga’s two most powerful clubs seem intent on eating one another.

The spark for all this is of course the charges brought against Barcelona this month in relation to payments made to Negreira during his time as a senior La Liga referee. Real Madrid have now formally joined the case, a process that allows them to support and present evidence, which of course they were always going to do.

This is already a scandal of jaw-dropping proportions. The period being investigated ranges from 2001 to 2018. During those years Barcelona won 10 league titles, four Champions Leagues and three Club World Cups, in the process establishing the Barça brand as a definitive modern sporting juggernaut.

The entire basis of Messi-dom, the greatest individual club career in football history, was pegged out around that timespan. Vast, fortunes were made on the back of it. In 2018 Barcelona became the first sports team to pass $1bn in annual revenues. All the while they were simultaneously paying one of Spain’s most senior referees a regular stipend totalling almost €7m. To give some context this is the equivalent of finding out Manchester United had Howard Webb secretly on the payroll through the Ferguson years; and then arguing in their defence that this should all be seen as perfectly normal.

Hence the public fury, the online howls, the hostile compilations of alleged refereeing oddities in favour of Barcelona overseen by the named parties; batted back with counter-outrage about Real Madrid’s own influence over all levels of power in Spanish football.

Looking back at the clips and the cuts in those slickly edited videos what strikes you is the epic shapes and colours, the iconography of what was, looking back, the greatest global club football show ever staged. Here is peak, hyper-elastic CR7 hurling himself with thrilling athleticism to the turf. Here is a boyish Lionel Messi looking baffled. Here are beautiful, glossy shots of the centre of the sporting world: Pep-José, Catalonia versus royal Spain, a celebrity two-hander that drove the commercial growth of the global game more than any other single event. What would it mean to tarnish that era now, to start pulling down those statues and throwing them into the harbour?

It has been reported that Barcelona’s directors will argue Negreira was paid only to redress what they saw as bias towards other clubs, a kind of backdoor vigilante refereeing justice. It has also been claimed that Negreira threatened to go public if the payments were stopped, a statement that, if true, skirts pretty close to an admission of wrongdoing (what, otherwise, would be wrong with going public?).

Beyond that the line from Barcelona seems to be the payments were in return for “scouting reports” with the implication that everyone else is up to this too. The president, Laporta, denies any wrongdoing, insisting that Negreira worked as an adviser, preparing reports and guiding players on refereeing issues – something Laporta described as “very normal”. He will give evidence, with a chance the former Barça coaches Luis Enrique and Ernesto Valverde will also be dragged in.

In reality the likelihood of Barcelona being stripped, banished or financially pummelled seem remote. Which interests exactly – which source of power and wealth – would that serve?

Potentially this might present an obstacle to the stadium rebuild plans, which involve taking out a €1.5bn loan. This is a club jacked up precariously on their own economic levers, hostage to a vast debt secured via their own good name, the certainty this thing will always continue to generate excess revenue. And that is arguably what is at stake here, the basic energy source, the purity of that name,

Is it going to be possible to maintain that highly profitable sense of Barça exceptionalism when the grim and granular details emerge?

Barcelona managed to retail the Més que un club shtick while wearing Unicef and Qatar Airways on the same shirt, like some rapaciously moralising two-face, and always presenting itself as the underdog; the ewoks not the Death Star. It all starts to look a little stranger if this version of the past takes hold.

These are tricky times generally for La Liga, which has struggled to match the Premier League’s combination of vast TV rights income and the presence of nation-state clubs with economic guarantees of their own. There is something touching, and perhaps just a little bit creepy about the jealous zeal with which the president of La Liga, Javier Tebas, talks about Kylian Mbappé, who is suddenly so vital to the vibes, the energy and aura.

This is a league that fed on stars for 15 years and where the president is suddenly acting as a kind of Pandarus, purring about Madrid’s enduring commercial power, aware of the vital uplift in interest and TV values his presence would bring to a league currently marinading in its own fear and loathing.

For now Barcelona will be narrow favourites on Sunday night. The referee story has coincided with three consecutive wins and a sense of galvanising fury. Only Bayern Munich have won at the Camp Nou all season. Pedri is back for Barça, Karim Benzema fit for Madrid. All that really seems certain is it should be tight, angsty and a little spiteful.

Some things, at least, don’t change.