The Home Office has rejected calls to end the detention of the children of asylum seekers at the Dungavel centre in Lanarkshire.

However, in response to a report from the Commons home affairs select committee, a series of measures aimed at improving their welfare have been agreed.

As part of the change, a Home Office minister will have to give authority before a child can be detained for longer than 28 days at Dungavel, while the education and welfare needs of any child will be assessed if they are staying for more than three weeks.

"There is concern about children being detained which I hope the measures we are announcing will go some way to alleviating," said immigration minister Beverley Hughes.

"It is only in the very, very tiny minority of cases where, either for reasons of their immigration history or because people have served a prison sentence, that we cannot put the parents into the community.

"In that situation we have to make a decision as to what is in the best interests of the children, and I think it is in the interest of the children to be with their parents, albeit that in that small minority of cases that parent has to be detained."

But the SNP has rejected her claims.

"The government said that children would only be detained there for a couple of days, we now have ministers saying that they will only become involved in these issues if a child has been there for 28 days," said party leader John Swinney.

"Now, I don't think a child should be there for a single day, that's my basic position, and I'm horrified that ministers are now entrenching their position as a result of the decisions made yesterday.

"I think it is immoral in principle for children to be detained in the prison that is Dungavel, there are alternatives available in our community to deal with people fairly and squarely."