Officers have been called to a serious collision in Upper Parliament Street.
Officers are at the scene of the incident and are working with the ambulance service and the City Council as diversions are put in place.
A man has been taken to hospital for treatment of serious injuries.
An air ambulance attempted to land in The Old Market Square in connection with the incident but was redirected to Forest Recreation Ground.
There is a police cordon between Market Street, across the Theatre Royal to King Street.
There are severe delays and diversions on the following services
Navy 49/Green/Orange and Pink line services – Please use Angel Row stops
Lilac/Red/Blue – Please use Pryzm
Blue/ – Use Woodborough Road
Turquoise Line – Please use Cathedral
— Nottingham City Transport (@NCT_Buses) September 18, 2019
🚨 Upper Parliament St is closed due to an incident, on our #thecalverton inbound we are having to drop customers off at the Victoria Centre.
outbound we are picking up from the Rose of England stop.
— trentbarton land (@trentbartonland) September 18, 2019