Seagull58
In the Algarve
Define 'ours'. If China invaded the Scilly Isles tomorrow, kicked off the islanders and put lots of Chinese on there, how long before we gave up and said 'okay I guess they belong to China now'? Five years? 180 years? This is why negotiation is appropriate.
The spanish briefly inhabited one of the islands then left of their own accord a few years before the british settled permanently on the other island. Argentina has never settled anybody on the islands and did not even exist as a state when the British settled there. Their sole claim to ownership is that it is only a few hundred miles away.