Europeans will be sent official alerts on their mobile phones if they are near a terrorist attack or natural disaster under an EU plan to replace the traditional emergency siren and reduce the risk of fake news causing chaos.

The lack of early warning for passersby at the time of the Westminster and Paris attacks, and the risk to lives posed by unofficial and inaccurate communications, prompted the move.

MEPs are expected to pass legislation on Wednesday obliging EU member states to implement the so-called Reverse 112 system which will alert people to threats and advise how to stay safe.

Tomorrow will mark the 3rd anniversary of #ParisAttacks 🇫🇷.

👉 The EU will soon set up a new warning system called #Reverse112.

☎️ Citizens will receive real-time alerts if terror or a disaster strikes. Watch and learn more: pic.twitter.com/M148PgCQu7 — EU Council (@EUCouncil) November 12, 2018

Similar systems exist in the US, but many European countries still use the same emergency sirens used in the second world war to alert citizens of an impending danger.

Where there have been moves to introduce modern systems by national governments, it is said to have been painfully slow.

The budget of the French authorities for alerting people via telephone networks was just €1.78m in 2017. The budget for updating the siren system that year was over €35m.

In a large-scale emergency, a lack of official instructions, fake news and rumours are said to be a threat to rescue operations.

European governments will be asked to work with mobile phone providers to bring in the new public warning system in which text messages will tell people the nature of the threat, its location, and the best next steps to take.

Benoit Vivier, public affairs manager at the Brussels-based NGO the European Emergency Number Association (EENA), which works to improve member states’ crisis management, said: “Take any of the recent large emergencies in Europe –whether man-made or natural – and you will realise in most cases modern public warning was not in place.

“We have the means and the technology, but so far we have largely failed to put them [to] good use. The new legislation ensures that from now on we do. This is an excellent step forward for the safety of Europeans.”

Levent Altan, executive director at Victim Support Europe, said: “We want a Europe that puts safety first and the new legislation is an important step to that direction. Modern public warning will provide people with the right information at the right time, leading to less victims and more lives saved.”

EU member states will have 42 months after the legislation comes into force to establish the emergency system. Should the British government secure an agreement on the terms of its withdrawal from the EU, the legislation will come into force during the transition period during which regulations from Brussels will be automatically adopted by Westminster.

Dita Charanzová, the Czech MEP leading on the Reverse 112 legislation, said: “As we mark the Paris attacks, and hope that such events never happen again, we must better prepare ourselves if they do.

“Europe’s new mobile public warning system will be an important tool in making sure that citizens get accurate information and instructions.

“Quick, reliable information will help to save lives. I am proud to have had an important role in getting this adopted and I only hope that member states will put the system in place even before the deadline to act.”