Suddenly stiff kitchen tap

First time poster here, and this might be an incredibly basic question, but I hope someone can help (without laughing too much!)

In the last 4-5 days the hot water tap in my kitchen has become incredibly stiff, in the last day or so it has been a real battle to turn on and off at all. The cold water tap doesn't seem to be any different than usual. Nothing out of the ordinary has happened to my knowledge, it's just suddenly got stuck.

I have no technical knowledge to explain things properly, but it is a mixer tap with the giraffe neck spout and usual round taps on either side at the base. I'm really not sure how old it is, but definitely more than 3 years, probably not more than 10.

Any ideas on how to fix it? It seems way too trivial to call a plumber out for, but I don't know what it needs? Oil? A large wrench?

thanks in advance.

Turn the water off, take the tap apart, splash some descaler over the moving bits and make them move in it, rinse, grease with silicone grease and put a new washer on, reassemble. Done.

morning pedantic

Gooooooooooooooooooooodddddddddddddd morrrrrrrrrrnnnnnnnnnnnniiiiiiiinggggggggg vietengland

just trade it in for a new fresh model. Much more satisfying than trying to fix up the problems of the old one.

Thanks for your advice ChrisR and htgeng. PEDANTICVINDICTIVEMAN will be thrilled to hear that I don't have a big enough wrench to take the tap off - I took a guess that that was the way to take a tap apart - so tomorrow I guess I'll either have to buy a bigger tool, or a new tap. I'm slightly dubious about buying a new tap as I'll then have to come back here and get step-by-step instructions on how to fit it. Or call a plumber. Or just stop washing-up.

Thanks again for your help, much appreciated

Bet it's from B & Q. Our hot tap has done this twice appaently it's the cartridge inside which you just have to take to the plumbers merchants, so that you can get the same thing. It was a quick easy job.