ALEX Salmond has blasted the home secretary on the UK's asylum policy, accusing the government of trampling on asylum seekers' rights by raiding families at dawn and locking them up in Dungavel detention centre.

The Sunday Herald has obtained letters between Scottish ministers and Westminster over asylum issues under the Freedom of Information Act. MSP Fiona Hyslop, secretary for education and lifelong learning, had been in correspondence with MP Liam Byrne, minister of state, about the treatment of failed asylum seekers.

In one letter dated May 20, she asks Byrne to clarify his position on why some families had been refused leave to remain in this country.

"Our understanding was that only those families involved in criminality or fraud would be refused leave, but it appears that some have been refused simply for having failed to report to the Home Office. To many this will not be recognisable as either criminality or fraud."

On June 6, Byrne replied saying that families "in the main ... do not fulfil the criteria that would allow the UK Border Agency to permit a grant. This will include families who have not abided by the laws of the UK by absconding and failing to report as required."

Byrne said that if a family did not return to their home country voluntarily, "enforced removal will be considered as a last resort".

The first minister wrote a strongly worded letter to Jacqui Smith on June 24 saying he was "deeply concerned" about families who have been refused leave to remain. He wrote: "A decision that they do not have a legitimate claim for asylum in the UK combined with their understandable reluctance to leave voluntarily should not allow us to trample on their rights as individuals."

A furious Salmond said it is "with increasing anger" that he had learned of families being raided at dawn and forcibly removed from their homes and "locked up in Dungavel".

The Sunday Herald reported in May that early-morning raids had returned to Scotland despite the Scottish government's clear opposition to the practice. Zodwa Mbali, a South African single mother, said eight immigration officers dragged her and her six-year-old son from her home in Drumchapel, Glasgow, and took them to Yarl's Wood detention centre near Bedford. Bridget O'Koro from Nigeria and her three-year-old daughter Osa were also taken by immigration officers to Yarl's Wood.

Salmond said he had "a number of concerns about how recent enforced removals have taken place".

Reports of between eight and 10 officers being used to detain single mothers struck him as "heavy handed". He has asked for Smith to explain why home detentions are only carried out in the mornings. "Surely it is possible to pick up a single mother and pre-school child at other times," he said.

An SNP insider told the Sunday Herald the party was becoming "increasingly concerned" by the recent actions of the Home Office in resuming dawn raids and detaining children in Dungavel.

"The Scottish government feels like they have made some progress in this area and we are very concerned about lapsing back into the old bad habits."

Patrick Harvie, Green MSP, said Salmond's critics will accuse him of "playing party politics" with the asylum issue. "They'll say he's kicking up a fuss and trying to pick a fight, but I think it's perfectly reasonable for the First Minister to seek the UK government on these matters.

"There should be nothing like Dungavel in this country and I think the letter is encouraging as it shows this government is willing to pursue the Home Office on this issue."

John Wilkes, chief executive of the Scottish Refugee Council, said it was "deeply concerned" by the detention and removal of children.

"It is hard to believe this exists in a 21st-century Scotland. We have condemned it, as have the Scottish government and Scotland's Commissioner for Children and Young People.

"The UK government has signed up to protect the rights of children under the UN Convention on the Rights of the Child, but shamefully except for children in the asylum and immigration system."

Wilkes said the SRC is in discussions with the Scottish government and UK Border Agency over alternatives to detention, but as yet nothing has been drawn up or confirmed.

A Home Office spokeswoman confirmed it had received the letter and that a response would be written to the first minister in due course.