Google is expected to accelerate the launch of its ambitious music service outside the US after the company announced last Friday that it will downgrade illicit filesharing sites in its search results.

Websites that host unlicensed copies of songs and films will be relegated in Google search results from Monday, in what is being seen as a major olive branch to the entertainment industry.

The change is expected to hasten the expansion of Google Music, the search engine's rival to Apple iTunes, which was announced in November 2011 but has been unable to expand outside the US because of licensing difficulties.

The music and film industries have complained for years about Google directing people to unlicensed material online. The prominence in search results of alleged illicit filesharing websites such as Pirate Bay and MegaUpload has become a major sticking point in Google's negotiations with the music industry as it attempts to strike licensing deals to launch its own service.

Geoff Taylor, chief executive of the British Recorded Music Industry (BPI), which represents the four major music groups in the UK, described the announcement as a breakthrough and said it would be helpful to Google's plans to launch its digital music service in the UK.

"This has the potential to be really significant, but it all depends how it is reflected in the results people see," Taylor said.

"It makes us feel that Google is a little bit more on our side. It's helpful background music to these [Google Music] discussions, certainly."

The BPI also wants Google to give internet users more information about licensed content in search results, so that queries for an Adele or Justin Bieber song would be more likely to return recommendations for Spotify or Last.fm.

Eddie Leviten, the head of communications at the Federation Against Copyright Theft, welcomed the announcement but said the devil was in the detail.

He said that some in the entertainment industry will be less than pleased with Google's plans to downgrade only the websites that have received the highest number of takedown requests from music and film groups. Under Google's new algorithm, if an infringing website is not subject to a copyright removal notice then it will not be relegated in search results; and every allegedly infringing URL has to be entered in a Google form, making the submission process slow and cumbersome.

Google also submits such requests to the Chilling Effects website, intended to show where freedom of speech is being restricted – but also in this case pointing to sites with infringing content.

Google says YouTube and other user-generated websites will not be negatively affected by the change. Music industry insiders say that was not anyway a significant issue because the video-sharing website offers a great marketing platform for emerging artists and already offers piracy protections, such as its Content ID technology, which identifies users who have uploaded unlawfully copied media.

"It's definitely a positive step but we need to see a little more about how it works," said Leviten.

Industry experts said the move was strategically linked to Google's plans to take on iTunes outside the US.

"This is a great political step forward for Google, said Mark Mulligan, a music industry analyst. "There is no doubt that what Google is doing is strategically linked to what they want to do with their own music service."

Mulligan said that forcing Google to demote pirate websites had been a top priority of the entertainment industry for the past 12 months, but the search giant had not previously shown signs of making any concessions.

"Google has a quite strident negotiation position," he said, adding that the move will smooth the way for Google to launch the most innovative next-generation music service in the market.