London Underground is to axe 400 office and management jobs and leave a similar number of vacancies unfilled, it was announced today.
The news was condemned by unions embroiled in a bitter dispute over the loss of 800 ticket office jobs, which has led to a series of Tube strikes and could lead to more disruption next month.
LU said it was reviewing all non-frontline services to make sure it becomes more efficient.
The Tube organisation said it had started consulting with unions over "necessary changes" to non-operational functions.
"LU is reviewing all non-frontline services to ensure the right levels of resources are in place, and to protect the twin priorities of delivering excellent daily customer service and the Tube investment programme, so vital to support the economy and growth of London and the UK as a whole.
"The review will reflect recent changes which have led to reductions in activity in some back-office areas, such as the changes in the formal contractual arrangements following the acquisition of Tube Lines.
"Customer facing and frontline roles, such as train operators, station and maintenance staff are not affected by this review. Around 400 permanent employees in back-office roles will be affected and a similar number of back-office posts which are currently vacant or filled by non-permanent staff will also be affected," LU said in a statement.
Managing director Mike Brown said: "Like all organisations we continue to face financial pressures and have a duty to be as effective and efficient as we can be. London Underground is vital to London and the wider UK economy and we must have an organisation fit to deliver our priorities - excellent daily customer services and the delivery of the biggest Tube investment programme in our history.
"This must be our focus. No customer-facing or frontline train, station, line control or maintenance roles are part of this review. We have committed to carrying out these changes as soon as possible to reduce uncertainty for those affected."
Bob Crow, general secretary of the Rail Maritime and Transport union, described the latest job cuts as "savagery", adding: "This underlines the deepening crisis LU is in.
"This is yet another tranche of job losses even before LU's wider review is finished and comes ahead of the Government's spending review announcement later this month.
"This is very much the thin end of the wedge and underlines how right we are to challenge the job cuts."
Meanwhile, the conciliation service Acas sent out a formal invitation to LU, the RMT and the Transport Salaried Staffs Association to attend fresh talks next Tuesday in a bid to resolve the ticket office jobs dispute and avert further strikes.
Mr Crow added: "It seems that the mayor is even intent on sacking some of the managers who have helped him to try to break our strikes."
TSSA assistant general secretary Manuel Cortes said the union was "fuming" over the latest job cuts, adding: "What makes this announcement even harder to swallow is that it has come on the same day in which a formal approach was received from Acas to all parties seeking to start formal talks aimed at resolving the current strike action on the Tube.
"It appears that the Mayor wants to scupper any attempt to return good industrial relations to London Underground and uninterrupted Tube services for Londoners. We've had plenty of bluster this week from Boris Johnson in Birmingham before his return to London to knife London Transport workers in the back without even having the nerve to engage with them or their representatives on his plans. It seems that Pinocchio Boris has become Boris the cowardly lion.
"TSSA will now be consulting our reps with a view to balloting our entire membership in London Underground. This announcement has come on the back of 800 operational job losses, and 500 engineering job losses. Our members will never accept that taking 1,700 jobs out of the network will make it anything other than a second rate and unsafe service."Reuse content