France and UK forge online counter-terror plan

The plan includes possibly imposing fines on social media giants for not taking down flagged online hate speech quickly enough. They also spoke about prying apart encrypted messages, which posed broader questions on civil liberty and cyber security.

But Macron said they first wanted to make sure internet operators "delete any content promoting hatred and terrorism in any way."

France has already passed rules that make it a crime to consult so-called terrorist sites.

The issue has led to one prominent Radio France Internationale journalist, who specialises in covering French jihadists, having his Facebook account blocked several times.

A Moroccan youth in France was also given a six month jail sentence last year for consulting the website of a US academic who works for a Washington-based think tank and who specialises in terrorism.

May echoed Macron's views and said that while cooperation between their intelligence agencies was strong, more should be done to tackle the online threat.

"We are launching a joint UK-French campaign to ensure that the internet cannot be used as a safe space for terrorists and criminals," she said.

May said the plan was to get companies to develop tools to identify and automatically remove the offending material.

"Our campaign will also include exploring creating a legal liability for tech companies if they fail to take the necessary action to remove unacceptable content," she said.

Such moves were likely to come under intense scrutiny from human rights groups given the documented abuse by the French state in curtailing peaceful protests under its ongoing state of emergency decrees, which have been in place since November 2015.

Cracking encryption

France and the UK were also hoping to get easier access to encrypted content, no matter where the data is localised.

France currently has no laws for mandatory encryption backdoors, but instead allows for government hacking to access pre-encrypted data.

A 2015 Intelligence Act gives French intelligence officers blanket immunity to hack computers abroad and also enables them to break into systems at home.

In 2016, the French version of a French-German joint statement on counter-terrorism also called for a ban on unbreakable encryption. The German version did not.

The UK can already compel the removal of encryption via its 2016 investigatory powers act. The British government also has the power to hack anyone's computer.

Pressure has been mounting for EU legislation on granting police forces access to encrypted data, with French and German ministers calling for an EU bill before the end of the year.

The European Commission is working on the technical and legal aspects of the encryption debate, and last week proposed granting police direct access, in emergencies, to the data held by tech firms.

EU justice commissioner Vera Jourova said she would be proposing a new so-called e-evidence bill sometime early next year.