Sticky substance

[GK Fanatic]

My sister in law is having a little bit of a falling out with her new neighbours over a large bush/small tree which is dripping dark sticky stuff onto their drive.
The leaves are skinny, a bit like weeping willow leaves and the branches are very dark almost black. Another clue is that wasps adore the sticky stuff. What kind of bush/tree is it anyone know ????

[monty0703]

the BBC gardening website or RHS site might be of use - both have plant identifiers you can use.

[GK Fanatic]

Thanks I'll try that