Police in London said a man who called the 999 emergency line to complain that KFC was out of chicken was among the most frivolous calls of 2018.

The London Metropolitan Police said more than 20,000 of the about 2 million calls that came into the 999 emergency line during the past year were for non-emergency situations, including a man who called to complain that KFC was out of chicken.

The department tweeted audio from the KFC call, as well as others including a person complaining about a bus being broken down.

Police said they also took calls about how long it took a pub breakfast to be served, a call complaining about a whistling bus driver and a call from a woman demanding a taxi cab be sent to pick her up.

A woman called 999 on New Year's Day to wish police a happy new year, the Met said.

"During the time that our call handlers are dealing with these time-wasting calls, a member of the public could be in real danger or have built up the confidence to call with an important piece of information that could take a dangerous person off the streets," Chief Superintendent David Jackson said.

"Imagine if one of your friends or loved ones was in need of the police as quickly as possible and it turned out we could not help because we were having to deal with one of these hoax calls -- I'm sure that you, like us, would be devastated and extremely annoyed," Jackson said.