One in 10 inner London residents left home during lockdown, mobile phone data shows

One in 10 inner London residents fled the capital during March’s coronavirus lockdown, according to researchers who used mobile phone signals to track the spread of the city’s residents into the home counties and beyond.

Around 10 per cent of 700,000 inner London residents on the O2 mobile network were no longer recorded at their homes in the weeks after March 23, when tough coronavirus restrictions came into place. 

If the same pattern occurred across the 3.2m residents of the 12 inner London boroughs and the City of London, it suggests around 320,000 people who live in the capital left at the start of lockdown.

The figures could add to suggestions that an exodus from the capital, where cases of the virus were highest in March, may have helped spread it across the country. Local politicians outside of London had pleaded with the capital’s residents not to fan out across Britain, fearing this would spread the disease.

Researchers at Telefonica, the Spanish company that owns O2, revealed the finding in a paper presented at the IMC 2020 internet conference this week.

While the researchers were not able to track individuals movements, they said they noticed spikes in areas of East Sussex and Hampshire at the same time, equivalent to an extended version of a phenomenon often seen at the weekend. This suggests it might be down to London residents moving to second houses or students coming home, although the researchers said the spread was possibly more dispersed than this.

Three-tier Covid lockdown map

People’s approximate locations were measured by looking at which radio towers mobile phones were connecting to, and said the data was aggregated so that they could not track individuals’ movements. 

The researchers looked at mobile connections made during nighttime hours to measure where people were staying so that the data did not merely reflect a drop in commuting patterns.

The research also showed a major change in people’s day-to-day movements during the lockdowns, with people moving around 50 per cent less than before when measured by the distance people travelled away from their homes and the variations in their daily routines. 

They found that the World Health Organisation declaring the outbreak a pandemic on March 11 had a small effect on movement patterns, with the lockdown itself proving more effective.

Studying traffic on the mobile phone network found that use of voice traffic also increased by up to 150 per cent as people turned to phone calls to stay in touch.