Union leaders claim hundreds of night buses face the axe to pay for London's new 24-hour Underground service.
The 'Night Tube', which starts in September, is expected to lose millions of pounds in its first few years.
Transport for London has admitted night bus services are under review to avoid a duplication of routes.
The TSSA union believes almost a third of the capital's night bus routes could disappear.
The union says its analysis reveals 47 out of 167 routes run in parallel with the Central, Jubilee, Piccadilly, Northern and Victoria Lines.
LU officials have already privately admitted to us that Boris's flagship Night Tube will not break even for another 17 years. It will lose £19.6m in running costs in its first full year of operation. Our detailed study shows that they will be running a duplicate tube and bus service in the middle of the night on nearly a third of all routes. Somethijhg has got to give and we think it will be the Cinderella night bus service.
Transport for London said it was planning a public consultation on the changes to the night bus network.
TSSA has simply plucked these numbers from the air. No night bus services will be cut to pay for the Night Tube, and to claim that hundreds of bus services will be cut is completely false.