LONDON (BLOOMBERG) - The UK is developing a "cell broadcast" system that would allow it to deliver alerts targeted to certain locations in an attempt to control the spread of the coronavirus, according to people familiar with the matter.

A basic text message telling people to "stay at home" and linking to more information was sent to nearly every phone in the country in March, after Prime Minister Boris Johnson declared a national lockdown to halt the spread of Covid-19.

The message couldn't be sent out simultaneously and took most of the day to reach everybody.

Government officials are now working with mobile network operators to develop a system that can quickly alert people in certain locations, according to the people, who asked not to be identified speaking publicly about private plans.

"We are always looking for ways to improve the UK's emergency communications and alert systems and regularly engage with a range of stakeholders - including mobile operators," a government spokesman said in an emailed statement.

The new approach comes after the UK ditched plans to develop its own contract tracing app in favour of implementing a version based on technology from Apple and Google.

The text system would rely on "cell broadcast," a separate technology to text messaging with its own broadcast channel able to function even when the main network is congested, according to the mobile industry lobbying group, the GSMA.

The British Environment Agency tested the method in 2019 using BT Group's network as a potential way of alerting people about flooding.

Countries, including South Korea, rolled out similar mobile phone alerts during the early stages of the pandemic.

The new approach could help health authorities get out messages about localised lockdowns, which have already happened in cities like Leicester where virus cases are deemed to be rising too quickly.

Technical details are still under discussion and software is being procured, the people said.