DUBAI—The development of the Great Britain island on Dubai's "The World" project has been thrown into doubt as its owners languish in jail awaiting trial for allegedly bouncing a check worth more than 200 million dirhams ($54.4 million).

London-born businessman Safi Qurashi and his business partner Mustafa Nagri, bought the Great Britain island in May 2008 for $60 million at the height of Dubai's boom through their property company Premier Real Estate Bureau.

The...