The marine reserve, put in place in 2010, effectively bans the Chagos islanders from returning home. The islanders are challenging it in the courts, arguing that the consultation that preceded the decision was flawed. The case was originally due to be heard this month but has now been put back.
The new evidence comes from recently uncovered documents about the 2002 feasibility study (which the Foreign Office had previously said did not exist) and newly released evidence from Foreign Office archives about historic fishing rights in Chagos.
Judges have also asked the consultant that conducted the feasibility study for the government to release all documents they hold that relate to it.
US diplomatic notes released by Wikileaks suggest that preventing the islanders from going home was in fact one of the governmentâ€™s intentions when it created the marine reserve. The Foreign Office officials named in the leaked cable will be cross examined as part of the judicial review.
A case by the Government of Mauritius at the International Tribunal on the Laws of the Sea will be heard in July.