The Conservatives are continuing to press Stephen Byers over his decision to approve adult magazine publisher Richard Desmond's purchase of Express newspapers.

Mr Byers claims a confidential Office of Fair Trading (OFT) report released on Monday proves he was simply acting on the advice of officials.

But the Tories say the report proves nothing - and the final decision would still have rested solely with Mr Byers, who was trade secretary at the time.

The row over Mr Desmond's purchase of the Daily Express, Sunday Express and Daily Star resurfaced two weeks ago when it emerged the publisher gave �100,000 to the Labour Party.

'Pornographer'

But Tory Trade and Industry Spokesman Nigel Waterson said he simply wanted Mr Byers to explain how he reached the decision.

"The advice now published only goes so far.

"The Office of Fair Trading only deals with competition issues.

"It hands firmly back to Mr Byers the decision on what they call 'non-competition' issues, which is jargon for rather politely asking whether Mr Desmond, as a pornographer, was a fit and proper person to take over a major national newspaper," Mr Waterson told BBC Radio 4's The World at One.

He accused Mr Byers of "ducking and weaving" on the issue and attempting to hide behind officials, when the decision was actually his.

"He has still not told us on what basis he made his final decison.

"His fig leaf that he relied on the advice of his officials has been ripped away."

Damaging speculation

Home Office officials told Mr Byers there was "no good reason" why Mr Desmond should not buy the newspaper group.

The advice is contained in the appendix of the OFT report originally meant for Mr Byers' eyes only.

The embattled transport secretary was hoping the report's publication would end potentially damaging speculation about his decision not to not to refer the merger to the Competition Commission.

In a statement, Mr Byers said "I publicly asked for this advice to be published.

"I am pleased that this has now happened, and that people can see the basis upon which I arrived at my decision."

Not 'well-placed'

Apart from competition issues, the OFT report looks at whether Mr Desmond is a "fit and proper person" to own a national newspaper.

The OFT said it had received 23 representations expressing "unease" about Mr Desmond as a publisher of adult material.

But there was no evidence to show that the editorial content of the newspapers has suffered since the merger, it said.

However, in its report, the OFT told Mr Byers it was not "well-placed" to advise on the ethical issues surrounding Mr Desmond's purchase of the newspaper group.

The OFT said it could only assess competition issues arising out of the takeover.

Any non-competition issues were "for ministers to consider should they wish to do so."

Labour donation

It concluded: "Overall we consider this merger is unlikely to have an adverse impact on competition in any relevant economic market."

But advice from the Home Office, also included in the report, said it could see "no reason for intervening based on the connection with adult magazines".

"The sale of these magazines was legal and there was no evidence to support the allegations made by some respondents that the link would produce adverse effects," the Home Office said.

Daily Sport

The Department of Culture, Media and Sport also said the case did not raise the same issues as Daily Sport publisher David Sullivan's attempt to buy a regional newspaper group in 1990.

The Competition Commission's predecessor, the Monopolies and Mergers Commission, ruled Mr Sullivan's proposed purchase would not be in the public interest.