The queue could stretch up to three miles long
People gather outside St Giles' Cathedral, in Edinburgh, ahead of the Procession of Queen Elizabeth's coffin from the Palace of Holyroodhouse to the cathedral.
The Rail Delivery Group has meanwhile warned those wanting to travel to Westminster Hall to expect services toThe rail operator's customer information director told the BBC people needed to plan carefully and allow plenty of time if planning to travel during the official mourning period. Transport for London also warned that roads and public transport in central London will be very busy and has advised travellers to allow"plenty of extra time" for their journeys and to avoid driving where possible.
Andy Byford, London's Transport Commissioner, told the national broadcaster:"We are working with our partners to keep our city moving smoothly and to ensure that everyone who is planning to attend the memorial events can do so safely."