Oleg Gordievsky, once head of KGB operations in Britain before his defection to the West in 1985, was accused of being 'a bit of a hired gun' and was 'still serving his paymaster' according to Rock Tansey QC, counsel for Michael Smith.
Mr Smith, 45, from Kingston upon Thames, south-west London, is charged under the Official Secrets Act with being a KGB agent and selling weapons secrets to the Russians.
In his summary, Mr Tansey referred to the evidence given by the former Soviet spymaster. Mr Gordievsky had said in open court that he now received a 'pension' from the UK authorities. He has also published two books on the KGB.
During evidence given by Mr Gordievsky, heard in closed court, he was asked about a map found in Mr Smith's home. The map was of Oporto in Portugal with marks that allegedly refer to meeting places during his claimed attendance at a KGB training course in 1977.
Before Mr Gordievsky was questioned on the map, the court, also in closed session, heard evidence from a senior MI5 officer, known as Mrs C. She had referred to a 'number 6' bus from a camp outside Oporto town centre.
The following day Mr Gordievsky resumed his evidence, and, according to Mr Tansey, 'with no prompt' began referring to the 'number 6 bus stop'.
If the court was supposed to be in closed session, said Mr Tansey, how did Mr Gordievsky know about the number 6 bus? Mr Gordievsky said he picked the number 6 'at random'.
The trial was adjourned until Monday.