Tactical voting, Sir Terry Wogan and performers of ambiguous gender are the guaranteed features of the annual kitschfest that is the Eurovision Song Contest.

But when Serbia was propelled to first place this weekend — thanks in no small part to the maximum points offered by six of its Eastern European neighbours — some commentators decried the victory as one neighbourly favour too far.

While historical alliances have long been tolerated as part of the Eurovision experience, cynics risked accusations of sour grapes by suggesting yesterday that unchecked block voting is putting the UK, one of its biggest financial contributors, at a disadvantage.

Last night’s results revealed that nations east of the Adriatic Sea occupied the top 15 places in the competition, in one of the strongest indications of the political alliances and unofficial voting patterns that have come to characterise the event.

In contrast, it was a humiliating evening for the four nations that bear the lion’s share of the costs of Eurovision, with the UK, France, Spain and Germany languishing among the bottom six places.

Serbia racked up 268 points, with eastern countries and all its fellow ex-Yugoslavs — even those that were its enemies in the wars of the 1990s — showing united support for Marija Serifovic. They included Croatia, Macedonia, Montenegro, Slovenia, Hungary and Bosnia and Herzegovina.

In an indication that Britain will have to try harder to offset the friendly alliances enjoyed by the Eastern European contingent, Scooch, a camp ensemble that had been thought to tick all the obligatory Eurovision boxes, found themselves virtually friendless. Scooch scored only 19 points, 12 of which came from Malta.

The league table, top heavy with triumphant entries from the Balkan and Baltic blocs, was in marked contrast to previous competitions, which used to be dominated by Western nations such as Ireland, France and, thanks to Katrina and the Waves in 1997, the UK.

Although some commentators enjoyed the flagrant bias of the voting, others expressed disappointment at its political nature, which they claimed threatened to overshadow the competition.

Pete Paphides, The Times music critic, said the eastward shift left the UK and all its future Eurovision hopefuls with a big challenge. He said: “The song needs to be spectacular to overcome what is now becoming a distinct disadvantage. I could not believe how many countries Eastern Europe and the former Soviet Union had broken into: they just kept on coming. Maybe a bit of humility and a recognition of how we are perceived by those countries might not go amiss.”

Eurovision websites were clogged with traffic from fans expressing various degrees of disappointment and delight in the aftermath of the three-hour final, which took place in Helsinki’s largest stadium on Saturday night, and attracted a British television audience of 10.9 million.

One fan fumed on an online forum that predictability, once affectionately tolerated by viewers, has now skewed the results beyond reason, and urged organisers to impose restrictions ahead of next year’s competition in Belgrade: “It is quite appalling that countries such as Malta, who year after year submit good songs, are block-voted out simply because they have no near neighbours. The obvious solution is to rule that countries cannot vote for their closest neighbours.”

The BBC denied that tactical voting had spoiled this year’s competition. A spokesman said: “That sounds awfully like sour grapes. Serbia won support from across Europe, not just its Eastern bloc friends.

“It is about more than just how the different parts of Europe vote, and at the end of the day, not even our Western allies showed much interest in our entry.”

Alan Howard, an expert in human geography from the University of Reading, who has surveyed 1,000 fans of the contest on voting tactics, said: “In general it seems that culture rather than politics is most important. Countries in Eastern Europe may well share a cultural affinity but in recent years the contest winner has garnered support from both East and West.”

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