He did not come back home by 9pm last night for his final meal, and did not respond to me ringing his bell either. I got a torch and had a walk round his "beat" to see if I could hear or see anything (as it was dark, I couldn't see much).
Both of us went to bed worrying and daylight could not come soon enough so we could go looking in earnest. Had on/off sleep until 2am. Partner went to make a cup of tea, and lo and behold, our darling boy emerges through the cat flap.
Alas something is clearly terribly wrong; he's meowing and moving with a great effort, clearly in pain. Something is very wrong with his back left leg and back end. If you tried to touch him he'd hiss and clearly was in major discomfort.
No signs of bite, blood etc so it's clearly an impact injury (hit by a car or booted by someone? We will never know). But it must have taken our poor brave boy some hours and a lot of pain and determination to get back to home and safety.
Sought advice and was told clearly not to wait for the vet to open at 9am but to go for out-of-hours consultation. So we did just that. The vet suggested could be a broken leg and has given him morphine to settle him down and relieve the pain. He will be x-rayed and examined more closely later and we have left him at the vets. The estimated costs at this stage for treatment is £3000 but thank goodness we have insurance so one thing less to worry about.
Just writing this down here has helped so thank you for reading so far. I have my mobile attached like glue as the vet will be calling anytime now to give me an update.