Radio National Breakfast is essential listening among the Canberra wonkery and so it was again this morning when Michelle Grattan dropped a tasty tit bit that Labor had “dirt” on an unnamed Coalition MP and might pull the trigger if the Craig Thomson allegations gathered any more steam.

The context was Phil Coorey’s story in today’s Herald revealing that in the event of a Liberal victory in a Dobell by-election caused by Thomson’s resignation over brothel expenses, ALP strategists might shift speaker Harry Jenkins to the backbench to preserve its House of Reps majority.

According to Coorey, current deputy speaker Peter Slipper would then ‘do a Colston’ and assume the speakership with Labor support. The Fisher MP already has form on the ratting front, having famously brokered a deal with Anthony Albanese to pocket an extra $30,000 as deputy speaker last year against Tony Abbott’s wishes.

Under the massively-unstable new paradigm, the Labor government would retain 75 seats (including Andrew Wilkie, Rob Oakeshott, Tony Windsor and Adam Bandt) with the Coalition on 74 (including Bob Katter and Tony Crook).

But here’s where it gets interesting. Crikey understands that the MP referred to by Grattan is none other than Slipper, or “Slippery Pete” as he is widely known on Capital Hill. He would presumably be assisted in his decision-making by an implicit Labor threat to detonate a dirty bomb if he failed to cross the floor.

Slipper’s document is said to be bulging.

For what seems like every second week for over the last two years the PANPA-award winning Sunshine Coast Daily, and News Limited’s Steve Lewis, have been writing about the very religious MP’s lavish travel expense claims.

In February, the Daily revealed that Slipper had spent long nights meandering in his Comcar to the vice hubs of Fortitude Valley and Kings Cross. In a six-month period last year the former Queensland Young Nationals president spent $31,805 on family travel and in has previously paid back $20,000 in wrongly-claimed entitlements.

And this FoI request, released in May, also got Labor tongues wagging. It shows three two-hour trips from Canberra locations to unspecified destinations “as directed”, when those trips should have taken 10 or 15 minutes.

More tantalisingly, last October the Courier Mail wrote that John Howard’s office was alerted by a senior Liberal MP of an “inappropriate” relationship between Slipper and a staffer, after Slipper apparently spent a weekend away with his charge at taxpayers’ expense.

Slipper, an ordained priest, has been a fervent moral values campaigner, writing to a constituent in January to reiterate his opposition to gay marriage. He heads something called the “Traditional Anglican Communion”, a group who dispute Anglicanism’s decision to ordain women and its latter day tolerance of homos-xuals.

The anti-Slipper putsch has been assisted by internal LNP supporters of former Howard government minister Mal Brough, who want to see the NT Intervention kingpin returned to the green leather. Brough, of course, is Sunshine Coast royalty, with brother and former Family Feud host Rob the popular nightly anchor of Seven’s local news.

For Labor though, the problem could be one of mutually-assured destruction. Tony Abbott has already hinted at the problems of a dirt war following Liberal Senator Mary Jo Fisher’s arrest in May for shoplifting and assault. And Crikey can think of at least one federal minister who also has a file detailing his dalliances with a staffer.

The Thomson case — which as Crikey reminded readers last week all started after the Dobell MP’s successor as the Health Services Union national secretary, Kathy Jackson, leaked a letter to the media in the midst of a Victorian factional battle for control of the union — could still have a long way to run.

Coalition eagle George Brandis announced this morning that he will badger the NSW police to open an investigation into the brothel charges on Thomson’s HSU credit card, claiming that its use contravened the NSW Crimes Act.