The sixth, and sadly, final episode of BBC2's documentary on London Underground staff goes "" (with apologies to The Jam) tonight and looks at what happens in the four-hour window when the power is off. The Tube , a six part series airing each Monday at 9pm, takes a behind the scenes look at the day-to-day running of the Underground. Tonight's episode focusses on overnight maintenance.

Getty Images/Peter Macdiarmid

They are using special fluffer brushes that helped them collect the dust and fluff from around the rails. This was important because if the dust built up, it could affect the trackside equipment or cause fires. Fluffers went to work every night once the electricity to the tracks had been switched off.

The film crew follow a number of Tube workers "." Fluffers is not what you might be thinking about the more modern day use of the term referring to adult films, but was (and apparantly still is) the name given to people who clean all of the fluff from Tube tracks. This was very much a female occupation in the past & they were also known as Fluffies. The picture of the women below was taken in 1955. London Transport Museum says: "Even in 1989, thanks to Molly Dineen's Heart of the Angel film, it seemed these cleaners were mainly female. It'll be interesting to see how many women (if any) are amongst the cleaners featured tonight.A pest controller, Mick, is also called in to investigate a smelly problem at Hounslow Central and emergency response worker Roy gets inside one of the Tube's disused 'ghost' stations , Down Street.There's a huge fascination with abandoned "ghost" Tube stations and I've been lucky enough to go on an awesome tour of disused Brompton Road station Tickets for semi regular / annual tours of Aldwych Tube run by London Transport Museum always sell out very quickly, so I imagine that tonight's episode will be intriguing and entertaining finale to the series.