Justice James Lewis of the British Indian Ocean Territory (BIOT) Court has ruled that Chagossians, who were expelled in the 1960s, have a right of abode on their homeland, dealing a significant blow to Keir Starmer's proposed deal to transfer the Chagos Islands to Mauritius. This landmark judgment overturns a 2004 law and previous rulings, concluding that the government's national security and defense arguments against return are no longer valid, especially given the acceptance of the islands' potential for population in the Mauritius deal. The estimated £51 billion cost of the Mauritius deal also invalidates the argument that returning Chagossians is too expensive. The ruling, which draws on the UK's UN obligations, makes transferring the islands to Mauritius nearly impossible, though the government has already appealed the decision.