But Mr Brown's inquiry into the Scottish MP's death is still likely to lead to the disciplining of Tommy Graham, MP for West Renfrewshire, against whom Mr Brown has now amassed considerable evidence. The Chief Whip is thought to have established that Mr McMaster was the victim of a whispering campaign about his sexuality even if this was not the cause of his death.
Mr Brown is now deciding whether Mr Graham's activities constituted a breach of the Standing Orders of the Parliamentary Labour Party, which forbid MPs to slander each other.
One source yesterday said that Mr Brown had made no decision yet, but Mr Graham's suspension was likely.
Mr McMaster's medical and psychiatric records are believed to reveal that the MP was both depressed and diagnosed as suffering from ME - the disease once known as "yuppie flu".
The rumour-mongering about his private life is thought to have worsened his plight, but not to have pushed him over the edge. A source said he was "not hounded to death but he was hounded".
Mr Brown's report is also expected to make recommendation about how the party deals with far-reaching allegations of sleaze in the Scottish Labour Party.
Senior party sources argue that the party's National Executive Committee already has sufficient evidence at its disposal to take action against one or two key individuals in Scotland.Reuse content