The jail sentences handed out last month to the four Swedish men behind The Pirate Bay, one of the world's biggest free file-sharing websites, have given a boost to the namesake party among young voters in Sweden, a recent opinion poll showed.

"It is definitely something that has put the spotlight on our issues," said Christian Engstrom, the party's top candidate for the European Parliament. "And it has demonstrated why it is so important, because the legal machine, if it's allowed to continue, is going to crush the internet, starting with the Pirate Bay and then continuing on to other enterprises."

A DN/Synovate poll ahead of the Europe-wide vote in June showed the party winning 5.1 per cent of the Swedish vote. That would be enough to secure the party, which wants to deregulate copyright, abolish the patent system and a decrease the level of surveillance of the internet, a seat in the European parliament.

The party was founded in 2006 and won only 0.6 per cent of the vote in the Swedish general elections that year. It is not linked to The Pirate Bay website, though some of its views coincide with those voiced by the Pirate Bay defendants.

The leader of the Pirate Party, Rick Falkvinge, believes that new Swedish laws, that for instance allow copyright holders to track down the IP-numbers of suspected file-sharers, are the main reason for the sudden popularity.

"We're seeing a shockwave of new repressive legislation that is seriously jeopardising the core of our civil liberties," he said. "People are starting to wake up to that fact."

What will decide the outcome for the party is simply the question of whether its sympathisers will turn up to vote in the election that is usually plagued by low voter turn-out.

Torbjorn Larsson, associate professor of political science at Stockholm University, said there was a risk some of the Pirate Party supporters won't show up.

"Young people have a tendency not to vote. But if this issue stays on the agenda up to election day, it will make a big difference," he said.