Harriet Harman has defended her actions in the Commons, after passing court papers given to her by her sister to another minister.

Sarah Harman apologised after a judge ruled she was in contempt of court, after passing on details of a Family Court case in which the mother was reportedly challenging a finding that she had harmed her child.

Speaking on Wednesday, the solicitor general insisted that she passed those papers to children's minister Margaret Hodge after obtaining legal advice from officials in her department.

"Before I sent the judgement, without the names, to the minister for children, I sought legal advice from my office and was advised that there was no prohibition on my doing so because the names had all been blanked out," she told MPs.

The advice was "subject to me checking with the solicitor that there was no specific ruling in this case prohibiting the disclosure", she added.

"Having checked with the solicitor, I then sent the judgement to the minister for children."

When the local authority challenged her actions, Harriet Harman contacted her official again.

"The lawyer in my office who advised me reconsidered the question and decided that he probably was wrong and that I should not have sent the judgement to the minister for children without a court order," she said.

"I can reassure the House I acted on legal advice. I did not identify the child - I could not in any event because I did not know the child's identity."

The Court of Appeal later gave leave for all the papers relating to the case to be disclosed to Hodge for her to consider whether she wished to intervene.

However, shadow attorney general Dominic Grieve, whose urgent question prompted Harman's statement, argued that it was "an extremely unfortunate state of affairs where the law officers' department...is unable to know the rules".

It was the role of the solicitor general "to take responsibility for their own actions in relation to documents that come into their possession", he added.