Well that didn't take long...
"Argentina has vowed to gain "full sovereignty" of the Falkland Islands after the UK gave up control of a remote archipelago"
The country's foreign minister, Diana Mondino, welcomed the step taken by Sir Keir Starmer's Government on Thursday towards ending "outdated practices" after Britain returned the Chagos Islands to Mauritius.
She promised "concrete action" to ensure that the Falklands - the British-controlled archipelago that Argentina calls the Malvinas and claims as its own - are handed to Buenos Aires"
And what with the UK now being a wounded beast after brexit, other countries realise that the almost definite support that could be relied on by the UK is no longer there...
Thus the decline in influence (along with economic performance) is inevitable, and will simply spiral until eventually the UK will lose it's seat on the Security Council.