Pride officials had an early start this morning, with Metropolitan Police officers phoning them before 6am to discuss the discovery of a suspected bomb on the parade route.
The area is still closed off as officers from the Counter Terrorism Command continue their investigations.
It is unclear at this stage whether tomorrow’s parade will go ahead.
Pride sources told PinkNews.co.uk that a cancelling the parade is “an outside possibility.”
“The fact is that the police just don’t know at the moment. They are fully aware of the impact it would have but you can’t rush a crime scene.
“They will pull out all the stops to get it re-opened.”
Haymarket is a key part of the Pride parade route and it would be difficult to safely re-route the tens of thousands expected to take part.
The head of communications for Pride, Colm Howard-Lloyd, told PinkNews.co.uk that security around the event is very high at this stage organisers were more worried about the weather than the bomb.
It is thought that the Met police do not think that Pride was the target, and that the bomb was being transported through the area.
It would be difficult to leave a car bomb for over 24 hours in central London without it being discovered.
Reports of a suspicious vehicle at around 2am led police to what they call a “potentially viable explosive device.”
A controlled explosion was carried out.
It is reported that the vehicle, silver Mercedes, was driving erratically before hitting a bin on Haymarket. The driver fled.