Not returning home.

I've not long got home from being on holiday and have noticed that blu (my cat) doesn't seem to want to return home. In the last 2 week's I have seen him once and that was on the street. Also this is unusual for him as he doesn't normally like going out.

Could anyone advise me on how to get him to come home?

Who was caring for him while you were away? Is it possible someone else in your neighborhood is feeding him, or adopted him thinking he was a stray? Have you tried calling him near dawn or dusk? Is he neutered, by the way?