"The prime minister is obviously very distressed for the family," the spokesman said minutes before Blair touched down in Tokyo on the first leg of a tour of East Asia.

"I do not think today is the time to rush to judgement or jump to conclusions," the spokesman told reporters aboard Blair's plane.

The spokesman said Blair spent "a fair amount of time" on a secure satellite telephone with London after being informed of the body find, speaking with cabinet ministers including Defence Secretary Geoff Hoon.

Kelly, 59, has been identified as the possible source behind a BBC report in May that Blair's office had "sexed up" a dossier on Baghdad's weapons capabilities that was used to justify the war on Iraq in March.

Kelly disappeared on Thursday, two days after facing a parliamentary committee investigating the affair. During his interrogation, Kelly denied being the main source for the BBC report.

Kelly told his wife on Thursday afternoon he was going for a walk and never came back.

Police spokesman said there would be no formal identification of the body until Saturday.

Sky News's respected political editor Adam Boulton, who was on the plane with Blair, said if the body proved to be that of Kelly it could lead to "a full-scale government crisis".

WAR.WIRE