Governments that attempt to regain control of the internet pose the greatest threat to innovation online, a senior adviser to Hillary Clinton has warned.

Alec Ross, an adviser on innovation in the US state department, told a conference in London on Wednesday that governments across the globe will soon begin "lashing back" in a bid to regain control of cyberspace.

"The biggest threat to your ability to innovate actually comes from government, and I say that from Hillary Clinton's office in the state department," he told the Le Web London conference.

"What I think is going to take place – and that is of marginal awareness to the digerati right now – is I think you all need to fear governments seeking to control our networks, seeking to take away your internet freedom."

Ross said he was not just referring to autocratic regimes in the Middle East, but included the US government in his remarks.

He highlighted the US Stop Online Piracy Act (Sopa), which attracted fierce criticism from open internet groups, as one example where the balance of power has shifted from government to organised groups online.

"This is why what was looking like it was going to become a piece of law flopped like that and is now gone," he told the conference for internet startups.

His comments reflect a growing mood of concern among internet advocacy groups. Sergey Brin, the Google co-founder, told the Guardian in April that the open internet was facing its greatest threat ever from a combination of government interference and control by private companies.

Ross said seeking to regain control of the internet through legislation or surveillance was pointless.

His pointed remarks are likely to be read with interest in Theresa May's Home Office, which is attempting to push through a bill that will allow authorities to track Britons' Facebook, Twitter, email and internet use for the first time.

Ross said: "What you an all anticipate I believe is that as movement making accelerates, as innovation increasingly makes use of connectivity technologies, as countries pour massive amounts of money into things like surveillance and still can't control the information environment, as pieces of legislation with massive corporate backing get shot in the head because the citizens set up networks, one of the things you can expect is a lashing back from government and it's something you should always be aware of."