Locks that work

You know your circumstances, of course, but even good ground anchors are not expensive, and fixing one is just a matter of drilling a couple of holes, then screwing in the supplied security bolts. It's nreally ot a big deal. If you're going to be there for a couple of years, it would be well worth it. Even a couple of months, maybe.

I have a friend who's a big motorcycle nut. For the one year he was in his last house the cost of a ground anchor was less than half the reduction in his bike insurance cost. The landlord was quite OK with it as he knew the sort of people likely to rent the property would have bikes or a scooter. We just lifted one of the flags and filled the hole with concrete. I doubt the whole mission cost more than £15 plus the screw in anchor.

Y'know what, I just had a look and you're quite right, I had no idea they were so cheap and (relatively) easy to install. There's one (www.torc-anchors.com) that uses resin, so you don't even need to concrete it in. And they're so small that I'd feel much more comfortable approaching the landlord. Thanks for making me see the light on this!

If it's really not an option then maybe look at other approaches such as Plantlock:

http://www.frontyardcompany.co.uk/products/plantlock.html

Nothing to stop you making something similar yourself with a metal bin, holes either side and run the chain through it, fill it with soil to give it mass. Combined planter and bike lock in one. While the bin might not be reinforced it would be a git to get the chain out of there.

That looks even better, though, it looks nice and you can take it with you when you move like a piece of furniture. Shame it's so pricey... a DIY metal bin job could work though. I'll have a dabble in the crazy world of metal garden bins.

Failing that just buy more bikes to lock together :)

Winner! :D

I've seen those before and avoided locking my bike to them as I always assumed that the bars you lock your bike to were essentially gas pipe, but reading that brochure it turns out I could not have been more wrong. They are really cool.

Yeah, the brochure makes it sound really, really secure, very impressive.