LONDON

Thousands of residents in west London have been urged to remain “extra vigilant” after officials confirmed that data was taken in a cyber-attack affecting three local authorities.

The Royal Borough of Kensington and Chelsea, home to around 147,500 residents, said some information had been copied from its systems during an attack earlier this week.

The council said it believes the theft relates to “historical data” but is still examining whether any personal or financial details belonging to residents, customers, or service users were involved.

“With advice from the National Cyber Security Centre (NCSC), we are encouraging all residents, customers and service users to be extra vigilant when called, emailed or sent text messages,” the council said.

The borough, Westminster City Council, and neighboring borough of Hammersmith and Fulham were all affected.

Westminster confirmed on Friday that the incident disrupted IT systems shared by the three authorities, including phone lines, and said it was working with the NCSC to maintain essential services.

Hammersmith and Fulham said it was “working around the clock” to restore its systems.

The borough said it was cooperating with the National Crime Agency, London Metropolitan Police, and NCSC to identify those behind the attack. The council expects at least two weeks of “significant disruption” as it works to bring systems back online.

Public bodies and companies across the UK have faced a sharp rise in ransomware attacks in recent years.

In 2020, a ransomware attack on Hackney Council encrypted 440,000 files and resulted in a reprimand from the UK’s data watchdog.