The London Eye wheel is lit in blue in support of the Clap for Heroes campaign following the spread of the Covid-19 pandemic, London, Britain, Jan. 7, 2021. (Photo/Agencies)

The Trafalgar Square fountains in London, which have been lit up blue in a renewed gesture of thanks to the NHS and frontline workers, London, Britain, Jan. 7, 2021. (Photo/Agencies)

The Trafalgar Square fountains in London, which have been lit up blue in a renewed gesture of thanks to the NHS and frontline workers, London, Britain, Jan. 7, 2021. (Photo/Agencies)

Photo shows a NHS Ambulance with blue lights flashing in London, Britain, January 7, 2021. Iconic landmarks in London lit up blue in a renewed gesture of thanks to the NHS and frontline workers, London, Britain, Jan. 7, 2021. (Photo/Agencies)