Facebook and Twitter have been threatened with sanctions if they refuse to help a Parliamentary investigation into Russian interference in the EU referendum.

The chairman of the culture, media and sport select committee, which is conducting an inquiry into “fake news”, has given the social media giants until January 18 to hand over information the committee has requested.

Damian Collins said that if they fail to comply, the committee will consider sanctions that could be imposed, such as encouraging the advertising industry to withdraw business on “ethical” grounds.

Facebook and Twitter are believed to have been used by the Russians to spread false information during the EU referendum campaign, and the DCMS committee has asked the companies for details of the accounts and pages operated by Russians suspected of meddling.