Mail Online is reporting relations between supposed friends, Spain and the UK, went south when a Spanish OPV, the Tornado, (something very similar to the projected Offshore Patrol Cutter, the article has a photo) decided to poke around in the Gibraltar’s territorial sea.
The Spanish have been attempting to peacefully recover the strategic stronghold, ceded to Britain in 1713.
Britain’s naval presence there is normally limited to only two small patrol boats. The British are speculating that the Spanish are using the issue to divert attention from Spain’s domestic problems.
HMS Sabre, one of two 24 ton, 16 meter patrol boats based at Gibraltar
Chuck Hill's CG Blog 
Some speculation here, about how an armed conflict might go:
http://cimsec.org/europa-universalis-at-sea-strategizing-gibraltar/
This is all ridiculous. Great Britain and Spain are not going to let a shooting war break out over Gibraltar. Neither side would find any casualties over this issue acceptable. This is all huffery and bluffery. If anyone did pull the trigger, it would be Spain, but that would require the Spanish people to fall for the oldest trick in the book – when the gov’t is losing favor of the masses, start a war. Of course, it happened in Argentina a mere 30 years ago… The Brits could probably “win” this war before it starts by sponsoring some TV documentaries about the Argentinian hunta doing this and the British response, and then contributing some money to the current Spanish President’s opposition. 😉
No one expects anything to come of this, but it is the kind of non-sense coast guards get involved with. In this case the players are “navy” instead of “coast guards,” but the difference is minor.
Going at it again: http://cimsec.org/gibraltar-getting-bumpy/
British getting new patrol boats, but similar in type to the ones being replaced
https://www.navalnews.com/naval-news/2020/07/marine-specialised-technology-to-supply-new-gibraltar-squadron-fast-patrol-craft/