Providing free bus travel for all pensioners is an "inefficient" use of public funds, a report has concluded.
The study by the consultancy Oxera for the Local Government Association says councils would be better off targeting those who were most in need.
Free bus passes for over-60s in England were introduced by the government in 2008, but many councils say the funding arrangements leave them out of pocket.
But the LGA said ending such a "popular policy" would be "problematic".
Prime Minister Gordon Brown first announced the £1bn national scheme, giving pensioners a pass to use buses for free, in 2005 ahead of a general election.
And, at first, the policy was only for routes within the local council area where the pensioner lived, but the scheme was extended to allow unlimited travel anywhere in England between 0930 and 2300 for pass holders.