judges ruled yesterday that the diary of a Libyan defendant in the Lockerbie trial should be admitted as evidence.

The ruling was a small victory for prosecutors arguing the case against Lamen Khalifa Fhimah and Abdel Basset Ali al-Megrahi, who are charged with the bombing of Pan Am Flight 103.

The alleged Libyan intelligence agents are accused of sending a bomb-laden suitcase on December 21, 1988, the day of the explosion, from Malta, where they worked for Libyan Arab Airlines.

Both men deny conspiracy to murder, murder and a breach of the 1982 Aviation Security Act.

The trial was suspended for three days to allow the court at Camp Zeist to conduct a ''trial within a trial'' on the diary's admissibility.

Mr Richard Keen, for Fhimah, claimed Scottish police violated Maltese law when they confiscated the journal on April 22, 1991. It was recovered in a joint search by Scottish and Maltese police of a travel agency Fhimah started after leaving his job as station manager for the Libyan airline.

Presiding judge Lord Sutherland accepted that the diary's seizure violated Maltese law because Fhimah had already been identified as a suspect in the case. Nonetheless, he noted that the Scottish police were not informed of the potential violation by Maltese officers accompanying them in the search.

Mr Keen said his client was not concerned about the diary's contents, which had not been revealed prior to the ruling. But he feared prosecutors would give it a ''most incriminating'' interpretation.