Like Camp chicory coffee, ventriloquism and boiled cauliflower, it would never catch on if someone invented it now. And yet, tonight's Eurovision Song Contest will have millions of people stocking up at supermarkets this afternoon for the appropriate snacks and drinks. Scorecards will be lovingly fashioned, entrants scrutinised. In a sense, it shouldn't even be here.

An event conceived five decades ago to show off the new technology that was “Eurovision” - the ability to broadcast the same thing to several different countries simultaneously - has outlived its initial raison d'être.

But, of course, tonight, as with every other Eurovision night, it won't be the technology we'll be marvelling at. It'll be the absolute lack of any correlation between the songs' musical merits and how well they do.

It's nothing new, of course. One early memory involves sitting in the front room and naively gasping at the coincidence that entailed Greece and Cyprus giving each other 12 points each.

A year later, I was even more amazed when they did it again - especially given that Greece's song, a repulsively jaunty jingle about hitch-hiking - is still one of the five worst songs I've ever heard in my life.

Of course, when Greece and Cyprus did it, it seemed like a bit of fun. These days, it's a reminder that Western Europe has been reduced to the role of bystander in a mutual Eastern European back-scratching exercise. Serbia, Ukraine, Latvia and Estonia have all benefited in recent years.

Using rigorous academic research to confirm what the rest of us had realised several years ago, Derek Gatherer, a Glaswegian academic data analyst, observed that the Eastern European countries are voting in a more “clubby” way than before.

This year's contest held in Belgrade may yet be different. Faced with a bunch of persistent offenders, any primary school teacher will tell you that the only way to deal with the problem is to separate the culprits. In this week's semi-finals, the former Eastern Bloc countries, which by voting for each other have ensured a strong showing for themselves in recent years, were separated into two voting pools.

It seems to have worked. So long, bellowing Lithuanian man with hair borrowed from My Little Pony and a song borrowed from Barry Manilow's bin! So long Tereza, from the Czech Republic, with your atonal exhortation: “If you want to have some fun, Don't run!”

It all means that tonight Eurovision may yet to return to what it once was - an aesthetic free-for-all where the cultural predilections of different countries leave millions of people reeling at the randomness of what people consider to be a good song.

Even bearing that in mind, anyone with high hopes for Britain's Andy the singing binman from X-Factor might do well to remember that even the most bizarre past winners - say, Lordi's Hard Rock Hallelujah in 2006 or Herreys' Diggi-loo, Diggi-ley in 1985 - had tunes that you didn't actually forget while they were still playing them.

Over on the European mainland, declamatory, neighbour-upsetting rave pop is still bafflingly popular, so expect the ballbusting Swedish popstresss Charlotte Perrelli to do well with Hero and Iceland's Euroband to score highly with This is My Life. Pirates of the Sea by the Latvian Wolves of the Sea is a good outside bet.

But if there's any justice, a hairy unhinged Frenchman called Sebastien Tellier will steal it with Divine. And Cyprus's lilting bouzouki-flavoured ballad Femme Fatale, sung by Evdokia Kadi, will also charm the international voters. But then I would say that. I'm Greek.

Battle of the Bands - Who's odds on?

Russia 5-2

Ukraine 7-2

Sweden 13-2

Serbia 7-1

Greece 8-1

UK 100-1

Source: Betfred 3pm Friday

— Citizens of the 25 countries in the final can vote by telephone or text for their favourite songs during the contest. It is not permitted to vote for your own country's act

— The national broadcaster showing the contest in each country then counts the votes and allocates 12 points to the winner, 10 to second place and 8 points through to 1 each to the third to tenth-placed entrants

— At the end of the show, the hosts in Belgrade receive each country's scores and painstakingly calculate the winner live on air

Explore Music

• Festivals

• CD Reviews

• Live Reviews

• Classical

Editor's choice

• U2 at Nou Camp Stadium, Barcelona
• The 50 Best Movie Villains
• The 15 golden rules of theatre etiquette