She was run over by my husband as he pulled our car into the drive on Sunday night. And, as if that wasn't bad enough, my five-year-old son and I witnessed the whole thing.

I still cannot believe it happened.

One minute Tils was following us to the front door, the next minute she was going in the opposite direction right under the wheels of the car.

Some of my friends, in an attempt to console me, have suggested that Tilly – who was 18, which for a cat is pretty old – was, perhaps, losing the plot a bit mentally.

One friend said: "Cats are very clever you know. Perhaps she was just tired of life and decided now was the time to die."

Can cats commit suicide? I am not convinced, but I appreciate the sentiment behind it.

Needless to say we are all in a complete state of shock. My husband says he feels like a murderer, and although I have tried to assure him, time and time again, that there was nothing he could have done, I know it is little comfort.

I don't think it helped either, when Samuel went over to cuddle him and said: "Don't worry Daddy, Mummy says it wasn't your fault. . ." Before adding ". . .but it was really Daddy, wasn't it?"

Tilly was probably the best cat in the world. She was incredibly gentle and really affectionate. In the five years that we had had Samuel she never once bit or scratched him, despite much provocation.

It is fair to say that Samuel is bouncing back from this tragedy much better than David and I. After a good cry and a lot of questions about Jesus and heaven. . . he seemed more upset about the fact he didn't have a pet any more than the fact that Tilly had been killed. Although I think it is important for children to have pets, I cannot even contemplate having another one yet, so when Samuel asked a few hours later: "Can we get a puppy now, mummy?" I think he was quite shocked by my reaction: "No," I shrieked.

"What about a kitten?" he muttered.

(With a huge intake of breath): "Maybe, but I think we should give ourselves a chance to get over losing Tilly first," I said. "Mummy is very sad she has gone."

"Okay, then," he said with a disappointed shrug.

A few minutes later however, he went over to the toy box where Tilly used to sleep, and lay his face on top of it, saying: "I wish Tilly was still here with us, mummy."

"Me too, darling, me too."

So four days after her death I still go home looking for her, still listen for the sound of her scratching the French windows to come in, and still can't bring myself to vacuum her fur off the top of the toy box because I find it vaguely comforting to have it there. . .

Let's hope time is the healer we are all told it is.