More cat poo than I ever want to see!!

Please help me, I getting more and more fed up of this. I have a 7 year old, neutered, semi-long haired, male cat. Everything was fine with him until about a week ago. I went away and left him at home with my cat loving partner. In this time he decided to stop using his litter tray and has now started to use various places downstairs on the carpet. His tray is very clean. Nothing has changed about his tray, he just seems to think the carpet is better!! The poo he does is always very runny with a few very hard balls of fur in. Can anyone suggest a solution for this somewhat unpleasant problem?
I have been back from my holiday for 2 nights now and he is still not using his tray. Please help.

Normally when cats poops/pees outside of the litterbox that means something's wrong- most likely he is sick- some kind of virus related to tummy. I'd recommend taking him to the vet ASAP to address this. This should solve the problem..
Good luck! keep us posted.

Please take him to the vet to be checked over. It could be the separation from you was to stressful for him and he has developed a problem health wise. Check him out with a professional quickly.

You may also need to use enzyme cleaner on the carpet. Once the smell is there, some cats will just keep going back to that spot. I had to treat a chair like that, and it worked amazingly well!

I took the cat to the vets today. He was given an injection of anti biotic and steroid. We came home with anti biotics and steroids. Already he seems to be happier.

Yay! Thank you for doing the responsible thing!