Can anyone identify this tree please?

 We're not sure if we planted it or it self seeded, but it's grwon very quickly and in about 2-3 years is now 10ft by 12ft. Haven't seen it flower or do anything interesting, but would like to know what it is so we can decide if we want to keep it or not!

Thanks

It's grown 10-12 ft in 2-3 years. Wow !!! That's incredibility fast. Cannot give an positive ID, but it looks suspect to me.

Looks like one of the many Willows.

Ive got a grafted Kilmarnock willow and that is definitely the same leaf. A seed dropped into another pot last year and its taken off like a rocket

This looks very like the one I've inherited on my allotment which I'm trying to identify.  It grew a few spiky but smooth catkin-type things in the spring, about 4 cm long, which disappeared.  It doesn't seem to get any flowers or fruits otherwise, but the lady who had the allotment before me was very fond of fruit trees.  If it's not likely to do anything I'd rather get rid of it, it's already about 8 feet high.  I cut it back quite hard in early spring, and it's grown back like mad.

Yes this has multiple branches - saw one today that was at least 40ft tall and I fear mine will get that big in another couple of years. Don't think it's a Kilmarnock willow as I had one of those and it looked different.