It was a beautiful evening in Madrid, the last remnants of afternoon heat settling on the city and a palpable sense of occasion in the air. After a late lunch of salt cod and octopus, we took the Metro and, accompanied by a saxophonist (buskers ride the train with you in Madrid), we arrived at one of the most famous arenas in sport.

The Estadio Santiago Bernabeu – named after a man who fought in the civil war alongside a key associate of General Franco, of whom more later – is the home of Real Madrid, giants of European football and one of the world's richest sporting organisations. To put their wealth into context, their playing riches dwarf those of Manchester City, their opponents on Tuesday night and themselves beneficiaries of the petro-billions of Sheikh Mansour. The Madrileños were able to field the world's most expensive player and even had someone who cost them €68m on the substitutes' bench. Around the ground, there are tapas bars and stalls selling confectionery. Opposing fans mingled, and exchanges were good-natured. It was – as far as you can manage it at a football ground – a civilised scene.

But suddenly sirens filled the air, and several van loads of police sped past us. They were on their way to a nearby bar full of Manchester City supporters, where, according to a number of reliable reports, they indiscriminately set upon the crowd, irrespective of age or sex, and encouraged them to leave for the ground by smashing them over the head with batons.

Shocked witnesses, some of whom had followed City for decades, said they had never seen anything like it. It was, at the very least, a heavy-handed approach to crowd control, but consistent with the history of Real Madrid and its rather dubious connection with law and order. Others have made the point that Real's all-white strip, a symbol of innocence and purity, is at odds with a past stained by its connection to fascism – they were Franco's team of choice, representatives of Mother Spain in the brutal fight against the Catalans of Barcelona. (Under Franco, Catalan was banned from being spoken in public, and in 1936 the Barcelona club president was murdered by Franco supporters.)

Down the years, players with a social conscience have shied away from taking the Real Peseta: the great Dutch player Johann Cruyff said he could not contemplate signing for “a team associated with Franco”.

Cristiano Ronaldo, pictured, had no such qualms when he joined for £80m from Manchester United. With a contract worth £10m a year, he is one of the world's highest-paid players, yet he has claimed to feel “sad” about his professional situation.

As we have clearly seen recently, football and politics are inextricably linked, and given that one's politics are a personal matter, let's just say I have my reasons this week for finding Cristiano Ronaldo a rather odious presence.