solicitors acting on behalf of a York double murder suspect are to take an appeal against his extradition to the Dutch High Court in The Hague.

North Yorkshire detectives will now have to wait several more weeks to learn if they can interview John Paul Marshall, 42, about the deaths of two men whose bludgeoned bodies were found in his Gillygate flat.

Their painstaking investigation into the gruesome murders, dubbed Operation Calendar, has so far cost more than £437,000, according to recent "major incident" figures passed to the Evening Press.

It was launched on December 6 after the partially-decomposed bodies of drug addicts Daniel Wall, 27, and Kevin Mulgrew, 38, were discovered by police responding to a complaint from neighbours.

A spokeswoman for the District Court of Amsterdam confirmed that Mr Marshall's legal representatives had submitted papers appealing against a decision made by judges two weeks ago to send him to England.

She said the case would now be transferred to a higher court at The Hague for a final appeal. It is uncertain how long this process will take.

Mr Marshall, an unemployed council tenant, has been held in custody in Holland since his arrest in Amsterdam on December 23.

Earlier that month police followed a trail of evidence from York to the Meanwood area of Leeds where his red Ford Fiesta was found, apparently abandoned, several days after he disappeared from his home.

Mr Marshall was last seen at the door of his Gillygate bedsit by a City of York Council plumber responding to complaints about what was thought to be water leaking into a bakery below on December 2.

When officers forced their way inside his home two days later they discovered the two men dead on the floor.

Both had died from head injuries inflicted during an horrific attack with a blunt instrument.

The bakery owners later gave up their lease after it emerged that the liquid had in fact been body fluids from the two men. The shop has since been refurbished and a new floor put in the flat.

Updated: 09:17 Saturday, March 20, 2004