Violent drug gangs are threatening communities in Sussex, a top police officer has warned.

Detective Chief Superintendent John Coles warned that Yardie-style gangs posed the biggest potential threat to policing in the UK after terrorism.

Mr Coles heads Operation Trident, which was set up by the Metropolitan Police in March 1998 as a London initiative to tackle gun crime in black communities.

He said that his officers have been forced to take up operations beyond the capital, including in Sussex.

He warned that the problem was threatening the whole country with the gangs spreading as far as Aberdeen and even targeting villages in Somerset.

"The Jamaican criminals are entrepreneurs. They will go anywhere where there is a ready market," he told the Guardian newspaper.

"Then there is the potential for conflict and shootings. The threat is that we are going to see it all over the place. It is spreading."

He added: "It has moved out of London to all the home counties. Next to terrorism, this is the biggest challenge facing police in London, and potentially the rest of the country."

Mr Coles stressed that the problem of drug gangs - once seen as the scourge of inner cities, mainly London - was now a "big issue" for the "white middle classes".