The pretext for Brown's journey is try to winkle out the truth behind the suicide of Gordon McMaster, the Paisley South MP, who is alleged to have been driven to his death by a whispering campaign among his colleagues in the Labour Party that he was gay and suffering from Aids. The Prime Minister wants to know what happened, and the Chief Whip intends to find out.
But Mr Brown will also cast his net over the wider conduct of Labour in Renfrewshire - Paisley is the county's main town - and examine specific allegations that membership lists have been illegally packed to influence candidate selections, and that links exist between Labour councillors and the laundering of drug money.
Even to someone as wise to the worst excesses of Old Labour as a chief whip, it is an extraordinary tale. Here in a town known to the world as the name of tasteful whorly pine-cone pattern - what could be more genteel than a Paisley shawl? - politics and organised crime are close acquaintances and a decent MP has been driven to suicide. Paisley people are known as "Buddies", but the politics of the place have earned its tabloid epithet - "a town called malice".
The Crown Office in Edinburgh is currently considering a report by Strathclyde fraud squad officers into the activities of a security firm set up with pounds 180,000 of public money as part of a regeneration scheme for a housing estate formerly used a dump for problem families.
Irene Adams, the Paisley North MP, named the now defunct FCB (Security) in 1995 as part of a brave campaign she and McMaster fought against the town's drug-dealing gangs. Both became the target of death threats. Adams alleged the security firm was being used to launder drug money. There were also charges that the firm applied heavy pressure to use its services and fiddled staff numbers to attract extra grant. Its parent company, Ferguslie Park Community Holdings, chaired by a Labour councillor, said an investigation had revealed nothing illegal and threatened court action against Mrs Adams.
At the same time, Labour's Scottish headquarters, Keir Hardie House, intervened to deal with claims that new members were being signed up in Renfrewshire branches - sometimes without their knowledge - in order to influence selection contests. This ruse appears to have been part of a concerted campaign to oust McMaster, Adams and Norman Godman, MP for Greenock and Inverclyde, and replace them with friends of a rival MP. Adams and Godman will both give evidence to Nick Brown about the smears they have been subjected to at Westminster and on their home patch.
For McMaster's version, Brown will have to rely on the suicide note found beside the body of the 37-year-old bachelor. Its full content has not been divulged, but in extracts the distraught MP asks how Tommy Graham, MP for West Renfrewshire, and Don Dixon, a former deputy chief whip, can live with their consciences. Both deny smearing McMaster, but Graham has kept an invisible profile his week, and was not even to be found at his cottage, "Sunny Govan", on the north-west coast.
If they get the chance, local activists will urge Brown to take a close look at Graham's selection process. One aggrieved member called it "an abomination". He referred to a report sent to Keir Hardie House claiming that 44 newcomers recruited from the local Royal Ordnance Factory had their membership fees paid by a single cheque from the TGWU, the transport workers' union.
Jack McConnell, Labour's Scottish general secretary, seems irritated by the rekindling of scandals in the wake of McMaster's death. After all, two Renfrewshire members have been expelled following the 1995 inquiry, and 50 to 60 dubious names have disappeared from branch rolls in the troubled constituencies. The organisation of Paisley North remains suspended. McConnell and council leader Hugh Henry pointed the finger at the behaviour of MPs rather than the Labour Party.
However, the sickness of intrigue, cronyism and petty abuse is by no means confined to Renfrewshire. Internal Labour inquiry has followed internal inquiry, from allegations of nepotism in Monklands, to electoral corruption in Glasgow Govan. Mohammed Sawar, the Govan MP, remains stripped of his parliamentary party "privileges" while police investigate claims that he gave pounds 5,000 to an election rival.
Though the Blairite Jack McConnell believes the warring fiefdoms are slowly being broken up, the big test for the Labour leadership is how it deals with the group that runs Glasgow City Council. In September, Labour's National Executive will consider a report into the "junkets for votes" scandal which rocked the council early this year. Bob Gould, the group leader, blew the whistle on his own fractious colleagues, alleging councillors had demanded foreign trips in exchange for their votes.
The rottenness endemic in much of west of Scotland politics stems from the fact that for decades Labour has been the unchallenged Establishment. On Glasgow City Council it has 77 of the 83 seats. Bereft of an effective opposition, or any apparent ideological differences, many councillors have devoted themselves to internal squabbles, patronage and perks.
The inquiry kept Glasgow out of the limelight over the election period and no NEC action will be taken until after the referendum. But Tony Blair then has the opportunity to clean up the operations of Scotland's biggest council group and deal cronyism a decisive blow across the west. But if Labour is seen to duck a purge in Glasgow, and Nick Brown fails to get to the root of the poison in Paisley, voters further afield will wonder about the quality of Labour's contribution to a Scottish Parliament.Reuse content