Bulgaria's former King and Prime Minister, Simeon Saxe-Coburg has expressed his gratitude to all Bulgarians concerned about the health of his eldest son, who suffered a hellish crash accident four years ago.

"Kardam's condition continues to be very serious, but I am deeply moved by the fact that many people in Bulgaria are with us in our prayers and wishes for his recovery," Saxe-Coburg told 24 Hours daily at a cocktail, given earlier this week by Spanish Ambassador Jose Luis Tapia on the occasion of the country's national holiday.

Prince Kardam, 48, and his spouse, Miriam Ungria, barely survived a car crash near Madrid on August 15, 2008, when their car hit a tree and overturned. The wife had lesser injuries and has recovered.

Simeon told the daily that some of the world's most renowned neurologists have been summoned to help with his son's recovery.

"It is very tough for us, but we will never give up our hope," he added.

Simeon Saxe-Coburg often travels to Madrid, to be with Kardam, while his spouse Margarita is said to have been spending most of her time in the Spanish capital.