The Dungavel centre has been at the centre of controversy

The Scottish National Party wants Alvaro Gil-Robles to visit the Dungavel facility in Strathaven, Lanarkshire.

The call follows the deportation of the Ay family, who spent a year at the Dungavel detention centre.

Yurdugal Ay and her four children, aged between seven and 14, were flown back to Germany this week.

SNP Euro-MP Professor Neil MacCormick said he was writing to Mr Gil-Robles, the Council of Europe's Commissioner for Human Rights.

"There is no doubt that the jailing of families and children for months on end at Dungavel, as was done to the Ay family, is a breach of fundamental human rights," he claimed.

"The UN Convention on the Rights of the Child states that the detention of a child shall be used only as a measure of last resort, and for the shortest possible period of time - yet the Ays were jailed at Dungavel for over a year.

"At home, Her Majesty's Inspectorate of Prisons recommended that children of asylum seekers should not be detained in detention centres for any more than seven days - and it is interesting to note that the Ay family are not being confined in Germany."

Professor MacCormick wants the commissioner to investigate the situation at Dungavel.

The four children did not receive mainstream education

"I hope that he will respond positively, and that this can be part of the pressure forcing the government into a change of policy regarding the treatment of these vulnerable people," he added.

The Ay family was returned to Germany after a final appeal was rejected by the House of Lords.

Lawyers acting for the family plan to appeal against the Home Office decision.

They Ays are also seeking refuge in Germany as the family attempts to avoid being returned to Turkey.

Yurdugal and her husband Salih are Turkish Kurds who fled the country 15 years ago for fear of persecution.

Mr Ay was last year deported to Turkey after returning to Germany to attempt a new asylum appeal. He has not been heard from since.