Our cats fighting

Question
Hello

We have two cats who are roughly the same age (about years old) they are not from the same litter.

They usually get on fine,they occasionally had a bit of chase-me-charlie up and down the stairs,  but in the last few days they have been very aggressive with each other, hissing and spiting at each other and really going for each other. Tonight they were  VERY VIOLENT to each other and him very worried, especially as they normally get on very well together.
At the moment I'm scared about going to work tomorrow because of what they might do to each other.  Is there anything I can do to calm them down and have things back to normal ?

Just to give you an idea of the two of them, they do have different personalities one is very affectionate and playful and the other was a rescue cat but we thought that he was now used to us and has been in a stable home for 3 years now.
It seems to be the rescue cat (Pilchard) who is attacking the affectionate cat (Misty ) but Misty does seem to be having a go at Pilchard as well.

Answer
Mark,

If I had to guess, there is a strange cat hanging around your house.  When they see this cat one or the other or both get into this fight/fright/flight mode and completely forget themselves and each other. This is not uncommon.  The best way to deal with it is to get them into an interior room where they cannot see outside and it is totally dark.  They should calm down and, in a few days to a week, return to normal.

Also, cats have very, very tough skin, there may be a lot of noise and some loose fur, but most cats will really not hurt each other, so unless blood is drawn, I would not worry too, too much.

Best regards... Norm.