Potsdam, Germany - Some 63 years after the end of World War II, a German prince is trying to secure the return of land and property seized from his family after an abortive bomb plot against Hitler.

Prince Friedrich zu Solms-Baruth, 45, is due to appear before an administrative court in Potsdam, near Berlin, on Thursday to pursue a claim against the Brandenburg state government.

The prince claims that after German reunification, his own father had "fought the German authorities tirelessly for restitution of the family's estates and property - until his death in January 2006."

A settlement was achieved between his father, the 4th Prince of Solms-Baruth, and the German government regarding the bulk of the estates in 2003. Prince Friedrich says what is now being claimed, is the rest.

The prince says it's difficult to put a price on the value of the land and properties. "However one could estimate that the forested areas alone are worth in excess of 7 million euros," he says.

The respondents in the claim are the Brandenburg state, the towns of Baruth and Zossen and several companies, including Deutsche Telekom and Thyssen-Krupp. Two preliminary hearings have already taken place, the first in 2006, the other last autumn.

The prince, who fears the Potsdam court might back Nazi law in the claim, has the support of expert testimony given by British historian Anthony Beevor and the German Institute for Contemporary History.

His German lawyer, Christian Linde, said Wednesday there had been "a new development in the case," that he planned to submit new evidence at Thursday's hearing.

Asked what action he plans if he loses, the prince told Deutsche Presse-Agentur dpa he would "appeal as many times as required and, if necessary, take the case to the European Court of Human Rights, as the case is fundamentally an issue of human rights and democracy."

"What we are dealing with here is stolen property which needs to be returned. No victim would allow a thief to keep what he has stolen - especially when it is the state which stands to benefit from a crime from which claims to protect its citizens.

"In this case, an ancestral home, built up over centuries was stolen, along with estates and companies which provided secure work, pensions and health-care for an entire region for over 500 years," he maintains.

A report by a German government department responsible for property rights had, according to the prince, initially found a clear legal basis for "a complete restitution of the properties." But later an opposing report had ruled otherwise.

The Prince claims the Nazis stripped his late grandfather, the 3rd Prince zu Solms-Baruth, of his rights of ownership over his company and estates in Brandenburg in the wake of the July 1944 bid to kill Hitler.

The day after Hitler escaped with scratches and bruises when a bomb concealed in a briefcase exploded beneath a table at his war- time headquarters, Prince zu Solms-Baruth was arrested by the Gestapo at Baruth Castle in Brandenburg, his ancestral home.

He'd known about the plot, says his grandson, "frequently secretly discussing it with those involved."

Incarcerated in the Prince Albrechtstrasse Gestapo prison in Berlin, dubbed the "House of Horror," he was kept in solitary confinement and interrogated incessantly, according to his family.

Others involved in the plot were also held there prior to their trial and subsequent execution. But Prince zu Solms-Baruth's life was spared.

The prince dismisses suggestions his grandfather received "preferential treatment." He was banished under pain of death from his former properties, and his rights of ownership over his companies and estates were taken from him," he said.

The day after his arrest, the Nazis "ransacked the prince's castles, threw out the family, felled timber in vast quantities and organised large Nazi Party hunts, treating the estates as if they were their own," claims Prince Friedrich.

Released near war's end, his grandfather fled to a small farming property he owned in Saxony, close to the Elbe river, with his wife, youngest daughter, and loyal staff, then to the home of his brother- in-law, the Duke of Schleswig-Holstein.

Later he stayed at Castle Hega, the home of the Crown Princess of Sweden in Stockholm, before leaving Europe to "begin a new life in Namibia with his wife, son and three daughters," explains Prince Friedrich.

His grandfather was regarded as a war hero there and was invited to settle in the country by General Smuts, the then South African leader.

"Sadly, he did not live very much longer, dying in his early 70s, his health undermined by years of war stress," the prince says.

"My father, the 4th Prince of Solms-Baruth, succeeded him and on a 50,000-acre (20,000-hectare) tract of land on which there had been nothing previously but 'stones, snakes and three sheep' later built up the second best-run farm in Namibia," the prince says proudly. (dpa)