Hopes of a last-ditch deal between the London Underground unions and management have been killed after peace talks at mediation service Acas collapsed on Friday afternoon (6 January).

The failure to find a resolution to the row over staffing levels on the Underground means a 24-hour walkout from station staff, represented by the RMT and TSSA unions, will go ahead from 6pm on 8 January.

"Despite huge efforts by the union negotiating team London Underground have failed to come up with any serious plans to tackle the staffing and safety crisis caused by the axing of nearly 900 safety-critical station jobs," said Mick Cash, the general secretary of the RMT.

"Instead of resolving the issues Tube bosses have chosen instead to ramp up the rhetoric with threats to mobilise a strike-breaking army of 'ambassadors' with severe consequences for the current safety regime across the Tube network.

"As a result of the management failure to face up to the current crisis the talks have collapsed and all industrial actions remains on. It is up to London Underground to take full responsibility for this situation and to come back to us with a serious set of proposals. "

The industrial action means the majority of stations in Zone 1 of the network will be closed, while Transport for London (TfL) has promised to deploy 100 extra buses and enhance river services in a bid to avert travel chaos in the UK capital.

Read more: Travel advice for the 8 January London Underground strike

"It is clear that some more staff for stations are needed," said Steve Griffiths, London Underground's chief operating officer. "We have started to recruit them and will continue to work with the unions to implement the recommendations made in the review.

"We believe that this will help us to provide a better service for our customers and ensure that they continue to feel safe, secure and able to access the right help while using our network. We encourage the trade unions to continue working with us in order to resolve this dispute and deliver the customer service our customers expect."

TfL apologised to passengers after an investigation by IBTimes UK discovered that at least 80 London Underground stations closed in December because of "staff absences".

UPDATE: 18:05 GMT -- The TSSA union has released a statement. They are in talks with London Underground on Saturday 7 January.

Manuel Cortes, the general secretary of the TSSA, said: "We are extremely disappointed not to have a solution to the dispute this evening but we have just been asked to return to talks with LU under the auspices of Acas in the morning. We will be attending and look forward to hearing what they are offering."

UPDATE: 21:25 -- Acas have confirmed that there will now be talks held on Saturday 7 January between the unions and London Underground. The RMT has U-turned on its earlier position.

An Acas spokesperson said: "We can confirm that Acas talks with London Underground, RMT and TSSA will take place tomorrow at 11am."