The Conservatives have released a confidential Commonwealth report on the deteriorating situation in Zimbabwe in an attempt to embarrass Tony Blair over his failure to confront Robert Mugabe.

The document was drawn up by Donald McKinnon, the Commonwealth secretary general, and has been circulated to the organisation's heads of government before their meeting in Nigeria later this year.

The Tories called on the prime minister last week to make it public, but Downing Street said it was unable to do so, arguing that it was a "privileged" document over which it had no authority.