UK emergency alert test: Three looking into why users failed to get text

A very small proportion of users on some mobile networks had not received the message, a government source said, and that failure will form part of the review.

The overwhelming majority of users who failed to receive the alert appeared to be with the Three network, but some on the O2 and Vodafone networks also reported difficulty. Users whose phones have not received a software update in more than two years, and those who were not within reach of a 4G or 5G network were not expected to successfully receive it.

The alert has also sparked conspiracy theories. Another Westfield shopper, 22, who declined to give her name, said she had received them on WhatsApp.

The government confirmed on Sunday evening that the Welsh language national emergency alert test contained a spelling error.

Instead, the plan faltered, with no department willing to take on the cost of rolling out the system, estimated at the time at about £1m. The Covid pandemic prompted the government to revive the plans after it was forced to work with the mobile networks to send a text message to all 85m phones in the country announcing lockdown.

The networks were overwhelmed and it took almost two days for all the messages to be delivered.