Global technology and telecommunications companies are objecting a proposed U.K. law that they say would let British intelligence agencies engage in mass surveillance and force them to give the government access to encrypted communication. The objections were submitted by the companies to a U.K. Parliamentary committee considering the draft legislation.

The proposed U.K. law, known as the Investigatory Powers Bill, would undermine customers’ trust in their products and brands, according to Facebook, Google, Microsoft, Twitter and Yahoo, which made a joint submission to Parliament.
Opposition has also come from privacy-rights groups.

The five U.S. tech companies expressed concerns that the law would impose requirements at odds with laws elsewhere. They also said other countries could enact similar legislation, creating a morass of competing and conflicting obligations as different legal jurisdictions came into contact.

The European Union in December announced a stringent new data privacy and protection regulation, motivated in part by concerns that U.S. spy agencies had been collecting vast amounts of European communications traffic and personal data. And data protection authorities in some countries have tried to mandate that companies notify them whenever approached by a foreign government for access their citizens’ communications or personal information. Yet, the companies said, the proposed U.K. law would in many cases make it illegal for them to disclose such demands, even in the course of challenging them before data protection authorities or courts.

A Joint Parliamentary Committee charged with examining the draft legislation has been holding hearings on the proposed law, which is expected to come to a vote this spring and, if passed, would take effect at the start of 2017.