McConnell increasingly isolated after Reid warning

While Mr McConnell supports the right of Catholic adoption agencies to be exempted from having to consider gay couples, John Reid, the Cabinet's most senior Catholic, made clear there should be no opt-out.

While the government is moving towards backing the full implementation of equality laws with no exemptions, Mr McConnell and the Scottish Executive insist they are in favour of an opt-out for Catholic agencies, even though it is a reserved issue and, therefore, Westminster can override adoption legislation in Scotland.

In the run-up to the May election, the Catholic vote will be crucial in Scotland, but Mr McConnell also has concerns that there would be a disruption to placing vulnerable children in care if faith-based agencies were forced to close.

The Scottish Executive said its officials were in constant contact with counterparts down south on the matter.

"Our position is quite clear on this. When the Adoption Act was passed, Peter Peacock [the former education minister] wrote to the relevant ministers and we have been assured that this is being taken into account in the Cabinet deliberations."

But Mr Reid told a Westminster lunch that Britain's fundamental value of equality could not be overruled by religious organisations or ministers because they harboured "conscientious objections".

He continued: "Now, if that causes particular problems for people with conscience, we should try to help them to find practical ways round it.

"So if there's a transition period or, in Scotland, they spoke about other ways of handling this, by all means, do it. But it mustn't overrule the fundamental principle."

His remarks were also aimed at Cabinet colleague Ruth Kelly, the Communities Secretary. As a member of the Opus Dei prelature, she is lobbying for a compromise that will also suit the Catholic Church after an opt-out appeared increasingly unlikely.

Ms Kelly will come under further pressure next week when the government prevents a free vote on the Equality Act.

Yesterday, Mr Reid said ministers' duty to Parliament had to come above their own beliefs. Referring to the only Catholic president of the United States, he said: "Jack Kennedy said when you take on an office of state, then your responsibility to the state and to the people of the country takes priority.

"If somebody says to me: I'm sorry, I'm not going to treat women as equal because my religion does not allow it, I say: tough, you're in Britain and that's a fundamental value in Britain and everyone has to accept it.

"If somebody says to me: within the law, if you say that, I'm going to hit you because that's my religion, I say: tough. This is Britain, and within the law you say what you believe."

Tony Blair is due to announce a decision on whether Catholic agencies should be exempt, but ministers have threatened to resign if he does not impose an outright ban on discrimination against same-sex couples.

The Prime Minister yesterday declared he was in favour of the rights of gay parents to adopt, but said a solution had to be found that had the interests of the children at its heart.

Despite Downing Street insisting that there would be another few days of deliberation before a decision was reached, Alan Johnson, the Education Secretary, predicted yesterday there would be no exemptions.

Any opt-out would constitute "plain, simple discrimination", he said, joining ministerial colleagues Harriet Harman, Lord Falconer and Peter Hain to object to the proposed exemptions.