It comes after reports of a Belgian security operation in central Brussels last night, as the Belgian government confirmed it was continuing its national threat level to its highest level.

Some 22 raids were carried out yesterday across Brussels and Charleroi, with Belgian police making 16 arrests in anti-terror raids, although the suspected gunman of the Paris attacks – Salah Abdeslam – remains at large.

The public in Brussels have been advised to “avoid places where there is a high concentration of people including concerts, large events, stations and airports, public transport, busy shopping centres; follow the advice of local authorities and respect security controls”.

The Brussels metro network will also remain closed on November 23, with a number of public events set to be cancelled and tourist attractions closed, the FCO said.

There is remains a heavy police and military presence, including at transport hubs and public sites, with potential disruption across the transport network, and Schuman station currently closed, the FCO added.