Why Britain avoided a formal Falklands declaration

Why did Britain conduct military operations against Argentina in 1982 without declaring war?

The explanation is that Britain wanted to avoid enabling wider intervention, although the stated preference is that a declaration would have made matters easier.

Avoiding wider involvement is given as the reason for conducting the Falklands campaign without a formal declaration of war. The explanation focuses on leaving fewer openings for other powers to enter the conflict. The stated judgment is nevertheless that a declaration would have made matters easier. No specific legal mechanism or alternative operational order is developed.