The UK has formally requested the status of “neutral observer” in a strategically sensitive legal dispute over possession of islands in the South China Sea.



The Foreign Office says the diplomatic move, in an area where Britain has no direct territorial interests, is a routine intervention in international maritime affairs.

But the timing of the request has prompted suggestions that Beijing has asked London to get involved as a potential go-between in the military standoff between China, the Philippines, other Asian nations and even the US.



China is boycotting the hearing, alleging that the permanent court of arbitration (PCA) in The Hague does not have jurisdiction to hear the issue. The UN-appointed tribunal adjudicates in international disagreements over maritime territory.

The case, which began on Tuesday, comes as China steps up its programme of building airstrips and defences in the contested Spratly Islands. Last month, the US raised the stakes by sailing a warship through a 12-nautical mile zone around two artificial islands in the archipelago. China responded by accusing the US of “provocative actions”.

The legal action has been brought by the Philippines, which accuses China of establishing illegal bases in its waters. The hearing is, unusually, entirely closed and confidential, although some neighbouring nations have sought observer status at the proceedings.



A Filipino soldier patrols the shore of Pagasa island, one of the disputed Spratly Islands in the South China Sea. Photograph: Pool/Reuters

On Tuesday, it emerged that the UK had asked to join the process, specifically seeking permission to be granted “neutral observer” status. The US, it is understood, has been denied the status because it has no territorial involvement.



It is not clear whether the Foreign Office intends to monitor the case full time. The UK has not taken a position on the legitimacy of rival, overlapping claims to reefs and atolls in the South China Sea.



The move came as a surprise to the Philippines, prompting speculation that London’s involvement was coordinated with Beijing after the the Chinese president’s visit to the UK last month.



The warmth of the welcome accorded to China’s president, Xi Jinping, by the UK government has opened a new era in diplomatic relations and initiated even closer economic ties.