Emails and internal papers passed to The Daily Telegraph reveal the Bill of Rights Commission is riven by division and unlikely to agree final proposals later this year.
The lack of agreement will make it difficult for the Prime Minister to persuade his Liberal Democrat colleagues to agree to a new British Bill of Rights when it reports back.
This could mean that any plans to replace the Human Rights Act, which currently enshrines the European Convention of Human Rights in UK law, will be pushed back until after the next election, which is expected to be held in 2015.