Hard wired smoke detectors - anyone know bout them?

Had a bit of a sleepless night last night, kept getting woken up, leaped out of bed with the landing smoke detector going off randomly

Hubby decided to switch them off at the fusebox, but STILL they kept going off, beeping this time, so he thinks the back up battery might be low! Anyhoo, just now, off they went again, and they're blooming horrendously loud, so can't stand another night of that, and they're switched OFF! What's going on then, anybody have a hubby who knows about these things?

He's going to take the cover off and see what we can do about the battery, or maybe it's a spider in there, in which case, I'll be long gone!

Mine are hardwired and they do have a battery which may be the issue, it usually is IME. I, who am the least house proud person in the universe, (although not quite in the category of those who feature in Grimebusters), hoover mine twice a year.........

Now I don't think that's quite true, considering you actually wash your mattress protector every week along with the bedding!

Well mine have been happily flashing away for 4 years now since we had the loft conversion done, and have to say, I've never hoovered them once, but then there's no dust in my house lol! There might be spiders though

He's up there taking it apart now, and I don't like the fact that they have something radioactive in there if you delve too deep It's the battery, and no dust, see, I told you!