The grandson of a German involved in the famous July 20 1944 plot to kill Hitler is a step closer to getting his family's confiscated property back.

Lawyers for Prince Friedrich zu Solms-Baruth said the Federal Supreme Court in Leipzig has overturned a 2008 ruling against the prince and instructed a court to hear the case again.

At issue is the return of vast properties in the state of Brandenburg that the Gestapo confiscated from the prince's paternal grandfather - also called Friedrich zu Solms-Baruth - who had taken part in the failed attempt on Hitler's life, orchestrated by Lieutenant Colonel Claus Schenk Graf von Stauffenberg.

The elder Friedrich zu Solms-Baruth was arrested on 21 July 1944 and forced to sign a contract handing over many thousands of acres of family estates and castles to Gestapo chief Heinrich Himmler.

About 5,000 people were arrested and 200 executed in the aftermath of this particular failed attempt on Hitler's life.

The prince was tortured but not executed

Prince Friedrich zu Solms-Baruth was tortured and forced to sign over his properties but was not executed - possibly because of his connections to Swedish royalty. Reportedly, Himmler was already thinking about negotiating a truce with the British monarchy via the Swedish Royal family, and did not want to burn his bridges.

Speaking before the original hearings in 2008, the 4th Prince of Solms-Baruth said his father had fought for restitution of the properties after German unification in 1990.

The current prince's father managed to reach a settlement with the German government over most of the confiscated properties before he died in January 2006.

Prince Friedrich zu Solms-Baruth picked up the fight for the remainder, and estimated they were worth 7 million euros.

The prince "is very patient, but he is completely determined to see this through as a matter of principle", said a spokesperson from PR firm Weber Shandwick, which is representing him in the UK.