A Scots-born killer serving 65 years in Washington State for first-degree murder took a step closer yesterday to being transferred back to Scotland to serve the remainder of his sentence.

Thomas Richey, whose brother, Kenny, is on death row in Ohio, could become Scotland's longest- serving prisoner, depending on the terms of any agreement between the Scottish Secretary and the US authorities.

His earliest release date in the USA is June 2036, and if he were to serve that length of sentence in Scotland it would cost the taxpayer about #1.2m.

A legal action by Richey was due to go ahead at the Court of Session yesterday, but Lady

Cosgrove was told that Scottish Secretary Donald Dewar has agreed to make a formal request to the US authorities for the transfer. The terms of the request will be thrashed out between Mr Dewar and Richey's legal advisers, who will try to satisfy concerns in the USA that he would be released much sooner here than in the States.

In 1987 Richey, 30, originally from Edinburgh, entered a plea of guilty at Washington State Court to one count of murder in the first degree and one of attempted murder. He shot a woman while high on LSD.

His brother, Kenny, 32, was sentenced to death in 1986 for starting a fire which killed a two-year-old girl.

Thomas Richey, who has not seen his mother for a number of years, wants to serve his sentence in Scotland so that he can be closer to his family, and first made a request in May 1988 to the US Department of Justice to be considered for a transfer.

The previous government agreed that he could be brought back to Scotland in terms of the 1983 Council of Europe Convention on the Transfer of Sentenced Prisoners and would be treated as serving a life sentence. His release before he had served 20 years would be considered appropriate only in exceptional circumstances.

However, in November 1991, the Department of Corrections of the State of Washington told the Department of Justice that Richey's transfer request would be refused because of the exceptional length of the sentence imposed on him and the loss by the state of its jurisdiction to decide how long he should serve.

Yesterday at the Court of Session, Miss Leeona Dorrian, QC, counsel for Richey, explained that in a letter in June 1997 Mr Dewar had written to Mr Alistair Darling, the MP for Richey's mother.

The letter said that, in principle, Mr Dewar was agreeable to the transfer, on the basis that Richey would serve the balance of the 65-year sentence in Scotland.

There had been a further development and the Scottish Office had faxed Richey's solicitors, indicating that Mr Dewar had now decided to make a request under the Convention to the relevant US authorities for Richey's transfer on the basis of the continuing enforcement of the determinate sentence of 65 years.

In that situation there was very little left by way of dispute between Richey and the Secretary of State. One of the main questions was the extent to which any restriction on Richey's release date might be imposed as a condition of the transfer.

Now that Mr Dewar had agreed to make the formal request, rather than litigate, it was in everybody's interest to see if there was common ground between Richey and Mr Dewar on the basis of which a joint approach might be made to the US authorities.

One difficulty had been the concern of the US authorities that Richey might be released much sooner here than in the US.

Lady Cosgrove agreed to continue the case for six weeks.

After the hearing, Richey's solicitor, Liesa Spiller said: ''We are very pleased that the Secretary of State has at this stage given an indication that a request will be made for transfer under the Convention on a determinate sentence of 65 years.

''We must now await the US authorities' response to that request. If there are further difficulties, we hope we and the Secretary of State will be able to work together to try to find common ground.

''For Mr Richey it is a big step forward. I think he will be very pleased.''