Argentina’s foreign ministry announced on 15 July that it had delivered a formal note of protest to the British embassy two days earlier, rejecting what it termed the “illegal” transit of the Royal Navy patrol vessel HMS Medway through waters it claims as its territorial sea. The disclosure came hours after the national football team defeated England in the World Cup semi-final and players unfurled a banner reading “Las Malvinas son Argentinas,” linking the diplomatic démarche to a surge of nationalist sentiment.

According to the Argentine foreign ministry, the Medway — permanently stationed in the Falkland Islands — sailed through the Argentine territorial sea off Santa Cruz and Tierra del Fuego in early July without prior notification, violating bilateral confidence-building agreements signed in Madrid in 1990 and updated in 1991 and 1993. Argentine officials argue the incursion contravenes UN General Assembly Resolution 31/49, which calls on both parties to refrain from unilateral actions while the sovereignty dispute remains unresolved. Foreign Minister Pablo Quirno stated that the protest reflected “the pride of being Argentine and the permanent defence of our interests.”

Downing Street did not directly address the naval protest but reiterated that the Falkland Islanders have repeatedly expressed their wish to remain a British territory and that their right to self-determination is paramount. UK Business Secretary Peter Kyle described the players’ banner as “completely inappropriate” and urged FIFA to investigate, noting that political messaging is prohibited under tournament rules. British officials have not publicly commented on the specific allegation of an illegal incursion, though London has historically rejected Argentine claims to the waters around the islands.

The incident exposes the fragility of the military confidence-building mechanisms that have governed the South Atlantic since the 1990s. Argentine naval tracking data, cited by local media, indicated the Medway was en route to Punta Arenas, Chile, when it crossed into waters Buenos Aires considers sovereign. The protest note, while dated before the football match, was publicised in a manner that analysts in Buenos Aires view as an effort to harness the diplomatic row to domestic political messaging. The dispute over the islands, which led to a brief war in 1982, remains a persistent irritant in bilateral relations. No further talks between the two governments have been scheduled, and FIFA has yet to announce whether it will open disciplinary proceedings over the banner.