Google will join forces with Wikipedia and other US technology companies to stage online protests against anti-piracy legislation, in the first co-ordinated political demonstration by many of the world’s most popular websites.

Wikipedia will begin a global blackout of its English-language sites on Wednesday, while Google will post a message on its US home page criticising the Stop Online Piracy Act and the Protect Intellectual Property Act currently being discussed in Congress. Wikipedia and Google are two of the five most visited sites on the web.

“As we saw in the Arab Spring, the internet gives new power to the public to engage in effective grassroots movements to change the world for the better,” said Jimmy Wales, co-founder of Wikipedia.