Negotiation expert Dr James Alvarez said that as night falls Raoul Moat will be more likely to give himself up.
He said: “One of the things that’s against him at this time is that he will eventually need to sleep, but there’s lots of police to take it in turns so they have the upper hand.
“People have natural body rhythms, the darker it gets the more people will want to go to sleep.
“The tendency will be for him to wind down.
“He’s probably already tired and worn-down and hungry. He will need a shower, that sort of thing.
“And psychologically he’s probably quite weak at this time.”
Dr Alvarez said that police will not want Moat to come to any harm.
He added: “One of the fundamental underlying principles is that if they’re alive, there’s hope.
“No negotiator ever considers it a success when a suspect gets hurt. They want a peaceful solution.”