Dibber, how deep should a wildlife pond be ?? I was told 60cm at least. Have a very small garden but would love a small pond (pondle)? ;D
Just to add to the information provided in other threads.
A pond should ideally be a minimum of 2 foot deep but would benefit greatly the deeper you are prepared to dig - I'm now on pond mark 3 and every time I have finished I have said that that will be the last time. Low and behold, a few months after I have finished I have read somewhere about the advantages of being 3/4/5/6 foot deep and hence I'm planning a bigger/deeper pond again.
In short make sure it's at least 2 foot deep, if you can be bothered digging deeper and your budget allows it then keep going as far down as you can. Remember though, extra depth is always better than extra surafce area so if it's a choice between a big shallow pond and a small deep one, the latter will always be better for the wildlife.
Not sure how you plan to build your pond but if you are planning on using liner then I've just bought some .75mm Butyl (with a lifetime guarantee) on e-bay for my small pond for £28 inc P&P - I've checked elsewhere on the net and it's at least double that. Give me a shout if you're interested and I'll dig up the name of the company that's doing it.