Proposals to tighten regulation on the internet to combat extremism and fine companies for failing to remove terrorist propaganda have been criticised by the Government's anti-terror laws watchdog.
Max Hill said the suggestion of punishing tech companies like Facebook and Google for not acting on unacceptable content was not the best course of action because they needed to be "brought firmly onside".
In a speech delivered at the Terrorism and Social Media Conference in Swansea, the independent reviewer of counter-terrorism compared the move to the actions of a Chinese dictator.
According to a report in the Times, he said the idea of punishing companies or their bosses for "not doing enough" to halt the spread of extremist material would be hard to implement.
He said: "I struggle to see how it would help if our parliament were to criminalise tech company bosses who 'don't do enough'.
"How do we measure 'enough'? What is the appropriate sanction?
"We do not live in China, where the internet simply goes dark for millions when government so decides. Our democratic society cannot be treated that way."
Mrs May outlined the idea of punishing companies such as Facebook, YouTube and Google if they fail to remove extremist propaganda and terrorist material from their platforms in the wake of the Manchester Arena bombing and two terror attacks in London.
She met French president Emmanuel Macron in June and said they were both determined to ensure the internet could not be used as a safe space for terrorists and criminals.
The UK and France are to develop plans to create a new legal liability for tech companies which fail to take action against unacceptable content.
Speaking at the time, Mrs May said: "The counter-terrorism co-operation between British and French intelligence agencies is already strong, but President Macron and I agree that more should be done to tackle the terrorist threat online.
"In the UK we are already working with social media companies to halt the spread of extremist material and poisonous propaganda that is warping young minds.
"I can announce that the UK and France will work together to encourage corporations to do more and abide by their social responsibility to step up their efforts to remove harmful content from their networks, including exploring the possibility of creating a new legal liability for tech companies if they fail to remove unacceptable content.
"We are united in our total condemnation of terrorism and our commitment to stamp out this evil."