Published Wednesday, 14 December 2011
A judge was told on Wednesday that the prohibition included within legislation was in fact intentional.
Mr Justice Treacy said: "How on earth a massive mistake like that could have been communicated to the House of Lords and nobody saw fit to (correct it), I have great difficulty in understanding."
The disclosure came as he adjourned a legal challenge to gay and unmarried couples in Northern Ireland being ineligible to adopt.
Lawyers for the NI Human Rights Commission, who brought judicial review proceedings, are now to seek documents relevant to the government position outlined in a separate case before the House of Lords.
Attorney General John Larkin QC, representing the respondent Department of Health, had resisted the request for the hearing to be put on hold.
"This is, with respect, an outrageous application," he said.
The Human Rights Commission is attempting to force a legislative change which would bring adoption laws into line with the rest of the UK.
It claims the current status, as it stands in the Civil Partnership Act 2004, is discriminatory and breaches human rights.
The challenge has been backed by an unidentified lesbian woman and her partner who want to adopt a child together.
A Stormont consultation five years ago showed overwhelming opposition to rights being extended.
Part of the case focuses on a landmark ruling by the House of Lords in 2008 where another unmarried Northern Ireland couple won an exceptional right to apply to adopt.
During those proceedings senior counsel for the Department, based on advice from officials, stated it was a mistake to include in the Act a prohibition on adoption for civil partnership couples in Northern Ireland, the court heard.
Monye Anyadike-Danes QC, for the Commission, said: "The upshot of that is that if you are in a civil partnership you can neither adopt as a single person or adopt as a couple.
"It wasn't until yesterday that we got the statement that the mistake wasn't a mistake, it was intentional."
Opposing her adjournment application, the Attorney General argued that it was irrelevant to the judicial review challenge because the woman backing the Commission is not in a civil partnership.
Mr Larkin, who was not involved in the House of Lords case, agreed that how those instructions were given "remains a mystery".
He said the direct-rule government operating at the time of the 2004 Act had been "holding the ring" ahead of public consultation two years later.
"It would have been striking if by the back door (of the) civil partnership legislation, there was some overwhelming transformation of the legal landscape on adoption.
"That is precisely what the government was trying to avoid," the Attorney General added.
But Mr Justice Treacy granted the adjournment due to the importance of the case and to allow the Commission's lawyers to deal with the sudden development.
It is due to resume again next March.