Unions have welcomed Andrew Lansley's description of the government's public sector pension changes as "unrealistic", claiming they have the support of a senior Cabinet minister.
In a leaked letter seen by the Daily Telegraph, the health secretary warned Danny Alexander, the chief secretary to the treasury, that the reforms were "inappropriate" and risked upsetting the coalition's "commitment to maintain gold-standard pensions".
The public and commercial services union (PCS), which represents public sector workers, and the TUC have urged the government to heed Lansley's words.
PCS general secretary Mark Serwotka said "even senior Conservative members of the cabinet can see there is an alternative".
"Andrew Lansley has said what public sector workers have known all along - the proposed pension changes are unfair and unsustainable.. This endorses the key points made by unions in negotiations."
Whereas Brendan Barber of the TUC said Lansley's letter "could have been written by any of the union negotiators".
Pension changes will force public sector workers to put more cash in their schemes, stay in their jobs longer, and receive a package based on their average earnings throughout their career rather than final salary.
Lansley wrote the memo two months ago, warning of the risk of industrial action and lower paid workers opting out of schemes entirely.
The Department of Health have claimed the situation has "moved on" since Lansley wrote the memo.