The UK's largest transport union, the Rail, Maritime and Transport Union (RMT), says it has seen an internal management report that shows hundreds of staff could be made redundant at underground stations across London, hindering safety and putting increased pressure on staff.
The RMT claims the London Underground report shows the tube operator plans to cut the number of staff at 70 tube stations.
Speaking with the BBC, Transport for London (TfL), which runs the London Underground, says it has no plans for any such cuts and accused the union of scaremongering.
The RMT said the report would leave 70 out of 116 sub-surface tube stations with just two members of staff, with a remaining 46 stations to be assessed at a later date.
The RMT said this could have a massive effect on tube safety.
In 1987 a fire at King's Cross station which killed 31 people saw minimum staffing levels introduced to increase safety across London's underground.
TfL has denied all claims made by the union and said it is committed to passenger safety and high standards.