There is an oak sapling growing about 4ft from the foundations of mine and my neighbour's house so I feel we need to relocate it. The problem is that is seems to be growing right at the base of a much more mature tree. If I start digging down surely I'm just going to hit mature roots and I won't be able to detangle the new oak roots. Any ideas? I'd love to have an oak in the garden but I'm not sure how to dig up the sapling safety and as easily as possible.
By the size of the sapling, this is not its first year - its root will have gone down a relatively long way, and you are right, you may well damage the roots of whatever tree is growing next to it in an attempt to take it out.
It does, however, need removing - if you cannot get the roots out, you will need to cut it down to a little stump, cut into the stump and apply a small amount of stumpkiller (such as SBK if you can get it where you are) otherwise it will simply regrow and keep on growing.