Police are seeking witnesses to what is believed to have been a deliberate collision between a motorcyclist and car on Saturday evening (April 20).
A 23-year-old man was seriously injured, including suffering stab wound, after the incident in Larkspur Drive at around 6pm.
Police say the man was knocked off the motorcycle he was riding by a car near the Friday Street junction.
The victim was taken by air ambulance to the Royal Sussex County Hospital in Brighton with serious back and arm injuries, including a stab wound to his back police said he suffered during the incident.
Sussex Police say he is currently in a stable and not life-threatening condition.
The car, described as silver VW Golf, failed to stop and drove away.
Detective Inspector Daniel Dugan said, “This incident may have caused another uninvolved driver to take evasive action and we would like to speak to this potential witness in particular, along with anyone else who may have seen something.
“We believe this collision may have been a deliberate act, but it is an isolated incident in which the people involved are known to each other.
“If you saw what happened or have any other information please contact us online or by calling 101, quoting Operation Foxmere.
“You can also contact the independent charity Crimestoppers anonymously on 0800 555 111.”
No arrests have been made at this stage.