Legal requirement between properties and extensions contained by uk? I live in a detached house and the subsequent door neighbour is...

I live in a detached house and the subsequent door neighbour is going to extend their house towards my direction. What distance can they move closer to my house?
Any websites with information nearly this will be greatly appreciated.
Answers:    Hi,Theoretically right upto their border(as shown on the deeds etc) but there are other law that they need to bear into account like-blocking daylight to any of your window that may be overlooked by the new build.
I will look for any relevent info and repost if I find any.
Richard.
right up to the boundary if local bye-laws apply ,you may find that you hold `no right to light ` also.
check near your local council as areas vary.