Several police units alongside colleagues from the Isle of Wight Ambulance Service rushed to the scene on Spencer Road at just before 13:00.
A police cordon is in place on Spencer Road with motorists unable to access the junction with West Street – which has also been blocked by officers.
The condition of the cyclist and the circumstances surrounding their injuries are currently unknown.
UPDATE @ 13:46 – The cyclist involved in the collision is said to have sustained serious injuries in the incident and has been taken by ambulance to St Mary’s Hospital for immediate treatment.
The road remains closed to traffic and pedestrians as officers investigate the exact nature of the circumstances leading up to the incident.
UPDATE SUNDAY @ 11:13 – Upon further investigation by local officers, it has been ascertained that no vehicle was involved in the collision.
It has been established that the cyclists brakes failed as she travelled down the hill on West Street, resulting in her hitting a kerb and colliding with a fence.
The woman’s injuries are not as serious as first though – although she has sustained a broken nose and cuts to her face.