The head of the Eurovision Song Contest, Svante Stockselius, told MediaGuardian.co.uk that potential changes would be discussed when the 42 participating countries meet next month.

"Every year, we evaluate and debrief each contest. We will discuss these things there," Stockselius said.

"We did a couple of big changes to this year's event, with the introduction of two semi-finals.

"We do not exclude that we will look into different changes for next year."

When asked if the poor performance of the "big four" countries could be down to other countries purposely voting against them, he replied: "It could be."

Stockselius added: "I don't think it is jealousy, but it might be that people think: 'Why should we vote for them when they are automatically in the final? Lets vote for someone else'. It could be something like that."

Making the "big four" compete in the Eurovision semi-finals could lead to them cutting their funding, but Stockselius said the scale of sponsorship the contest now attracts meant it could afford to carry on without this money.

"Of course we would have to look into funding, but we have such big sponsorship now it could manage," he said. "It would be a point of discussion."

The BBC's controller of entertainment commissioning, Elaine Bedell, told MediaGuardian.co.uk that the corporation was keen to talk to the EBU about potential changes.

"We are going to sit down with the EBU pretty soon to see what the best way forward is," she said.

However, taking part in the semi-final could lead to a position where the UK misses out on a place in the final.

This is a scenario the BBC would be keen to avoid when, due to its contract, it has to screen the three-hour final in peaktime on BBC1.

However, Stockselius said: "That is a question 38 other broadcasters have to face."

BBC sources said the corporation had an "open mind" about the UK potentially losing its automatic place in the final.

"We would have to think clearly about it, although it would be a bit odd giving over primetime without the UK in the final," one insider said.

Stockselius added that taking part in the semi-finals might be a decision the "big four" broadcasters should take for themselves in order to bring greater interest to the contest.

"Maybe it should be something for the broadcasters to consider," he added. "They would most probably get a better rating in the semi-final."

BBC insiders said that as well as potential changes to the contest's structure, questions also had to be asked about what acts the UK put forward in future.

"The viewing figures [for this year's contest] were fantastic, but we need to think about the sorts of musical acts we put forward in the future and how we want to approach it," a BBC insider said.

Stockselius said he did not agree with the argument that the "big four" would never win again, adding it was "fully natural and understandable" for countries to be disappointed when they did badly.