"It is extremely significant in gay history - it shows how much the world has moved on," said David Harvey, editorial director of 3Sixty magazine.
Sussex Police only lifted a ban on uniformed police marching in British gay pride events in 2004.
Saturday's parade starts from Madeira Drive and ends at Preston Park.
"The chief constable is making a statement about equality within the police," said Mr Harvey.
"Not only if you work within the police, but also how the police treat the community at large, everyone is being treated equally."
Joe Edwards became Chief Constable of Sussex in February
Some 120,000 people are expected at Preston Park, where police will be cracking down on drug dealers.
They are hoping to avoid a repeat of last year, when 13 people had to be treated for drug overdoses.
"Three of those were very close to being fatal and I would be neglecting my duty if I didn't pay attention to that," said Chief Supt Kevin Moore.
Sniffer dogs and Ion Track machines, which analyse palm swabs, will be used to detect controlled drugs, although police have pledged there will not be random testing.
"Dealers targeting the event have been coming year on year and selling to the occasional user and that's where the problem lies," said Pride organiser PJ Aldred.
"People who aren't used to drugs are being sold God-knows-what and it's nasty stuff."
Courtesy of the Full story from the BBC

