David Snoxell is Co-ordinator of the Chagos Islands (BIOT) All-Party Parliamentary Group.

The 1966 UK/US Agreement making the Chagos Islands (British Indian Ocean Territory) available for defence purposes and providing for a US base on Diego Garcia will be renewed for a further 20 years on 29 December. This presents a unique opportunity to resolve disputes, which have dogged successive governments, concerning the future of the Chagossians and of the Territory, excised from Mauritius in 1965. If the agreement is rolled over without addressing these issues the campaigns by the Chagossians to return to their homeland after 48 years of exile, and by Mauritius to regain sovereignty, are likely to intensify both at national and international level.

My earlier piece on ConservativeHome argued that the Government should take this opportunity to bring about an overall resolution of the issues – resettlement, sovereignty and the Marine Protected Area – before the 29 December deadline. A decision on resettlement would probably have been announced before the summer recess but for the change of Government in July.

The Chagos Islands All-Party Parliamentary Group has long argued that extension of the Agreement should be conditional on a commitment by both the US and UK to support and facilitate resettlement. The Group has 47 members from all ten political parties in Westminster. A further 38 MPs signed an Early Day Motion in the last session to this effect. David Cameron discussed the matter, as did Jeremy Corbyn, with President Obama during his visit to London in April. The President did not raise difficulties.

By a majority of 3:2 the Supreme Court decided on 29 June not to re-open the Law Lords’ 2008 majority judgment which had upheld the 2004 Orders in Council, banning return. Although a legal defeat, the tone of the judgment was a substantial moral and political victory for Chagossians. The majority concluded that although the new evidence was not sufficiently compelling to set aside the 2008 judgment the conduct of the FCO had nonetheless been “highly regrettable” in withholding important documents. The Court also sent a strong signal that in the light of the 2014 KPMG feasibility study, which found no obstacle to resettlement, maintaining the ban on Chagossian return may no longer be lawful. If the Government failed to restore the right of abode, it would be open to the Chagossians to mount a new challenge by way of judicial review on the grounds of irrationality, unreasonableness and/or disproportionality. The strictures of the Court and the prospect of continuing litigation, begun in 1999, may give the Government pause for thought.

The Supreme Court also gave Olivier Bancoult, the Leader of the Chagos Refugees Group, leave to appeal an Appeal Court decision in 2014 which had found that the Marine Protected Area, declared in 2010, was not motivated by improper purpose. The case will be heard next year. The Chagossians in Seychelles have also launched a judicial review in the High Court because they were excluded from the compensation in the 1970s/80s.

In a separate case brought by Mauritius, an international tribunal in 2015 found the MPA to be inconsistent with international law and upheld Mauritius’ right to eventual sovereignty of the Islands. The Tribunal requested both parties to work out a solution. Discussions between the parties have got nowhere because the FCO refuses to discuss sovereignty. However, in July David Cameron wrote to the Mauritian Prime Minster offering discussions on sovereignty in an effort to head off the Mauritian proposal to seek a resolution at the UN General Assembly in September, referring the issue to the International Court of Justice. Mauritius had indicated it would do so in June 2004, when I was British High Commissioner, but has held off for 12 years. So for the first time Chagos will come before the General Assembly.The presence of Olivier Bancoult in the Mauritian delegation will inevitably focus attention on the UK’s treatment of the Chagossians.

In December 2012 William Hague announced a review of Chagos policy, which still remains trapped in a Cold War time warp. It is perfectly possible that with compromise and diplomacy, an overall political settlement involving the US and Mauritius which supports resettlement, could be agreed by 29 December. This would bring an end to the tragedy of the Chagossians, to the UK’s international isolation on the issue and further costly litigation. It would lead to the legitimisation of the MPA and a beneficial and friendly relationship with a state which has a progressive economy and is a beacon of stability and democracy. In its letter to The Times of 4 July the APPG said: “It is time for a political decision which restores the rights of the Chagossians to return and to put this shameful episode behind us”.  A continuation of the Chagossian exile can only bring further shame on the UK.