A male cyclist hit by a lorry in Marylebone Road during Friday morning rush hour (June 8) was rushed to hospital.
The Met were called to the crash in Westminster shortly before 8am.
A male cyclist and a lorry were found to have collided in Marylebone Road at the junction with Cosway Street.
London Ambulance Service rushed the cyclist to a central London hospital from the scene where he remains at 11am.
A Metropolitan Police spokesman said: "Police were called at approximately 7.54am on Friday, to reports of a collision between a cyclist and a lorry on Marylebone Road.
"The male cyclist (no further details at this time) has been taken to a central London hospital. We await an update on his condition."
Metropolitan police confirmed the driver, who they can give no further details about at this time, was arrested at the scene on suspicion of driving whilst under the influence of drink or drugs and driving without insurance.
He remains in police custody.
Traffic in the area was slow as one westbound lane of Marylebone Road was closed following the crash.
It reopened at 9.30am but heavy traffic and delays affected the area until around 11am.