Sir Keir Starmer's close friend is Mauritius’s chief legal adviser, it has emerged.

The Prime Minister, who is facing widespread fury over the UK’s decision to hand over sovereignty of the Chagos Islands, will face further questions over his relationship with Philippe Sands KC.

Sands is the chief legal adviser for the island and has argued for Mauritian control of the islands.

He said in January: “At the outset, I wish to make clear that as a member of the Bar of England and Wales I have acted as counsel to Mauritius since 2010 in relation to the Chagos Archipelago.

“As such, I have been involved in the proceedings before the Annex VII arbitral tribunal (2010-2015), the International Court of Justice (ICJ, 2017-2019) and the International Tribunal for the Law of the Sea (ITLOS, 2019-2023).

“I continue to advise the Government of Mauritius.”

After news broke of the UK’s decision to give away the Chagos Islands, Mr Sands posted on X: “A special day for Mauritius, for Chagossians, for international law.”

Former Defence Secretary Grant Shapps raged over the decision on Thursday, declaring: “As Defence Secretary I was so concerned about the sovereignty of the Chagos Islands that I blocked the deal from proceeding.

“Today, this government has announced it's abandoned our sovereignty of the Archipelago, including the militarily essential Diego Garcia.

“The government's joint statement fails to address FOUR urgent questions:

“1. What happens after 99 years and specifically, is renewal then automatic? If not, then Starmer has just signed up to a Hong Kong style situation, which hasn't worked out well.

“2. Exactly how much is the new rental payment to the government of Mauritius? The sums being demanded were both enormous and indexed linked. The government must release this number immediately.

“3. How has the government ensured continued military use of Diego Garcia, especially since the location of these islands could be impacted by the Treaty of Pelindaba (also known as the African Nuclear-Weapon-Free Zone Treat).

“4. How will this capitulation help when it comes to protecting other British assets like Gibraltar, the Falkland Islands and our two Sovereign Bases in Cyprus - all of which face varying levels of sovereignty challenge?”