Apples on tree - no leaves

The apples on this tree are very small, one twist and they come off. There are hardly any leaves - just doesn't look healthy . Ive put a picture of a section of the tree,and close up of branches. Anyone got some ideas please - is it on its way out . Thank you

 

I wonder - How old is it, and does it have enough water?

 

I say it has canker

 

Are there any splits or damage anywhere on the trunk of the tree?

The lack of leaves and poorly formed apples points to a lack of water and nutrients from the roots to the branches and leaves.
As mentioned above canker can cause such problems.

 

Give it a good watering with a little feed, remove apples and wash the bark with something like Winter tree wash Tescos?

 

Thank you for your help, I thought it looked like canker but I wasn't sure - im not sure how much is a lot - do you just treat it kikw vlaxj spot on roses - cut it off and destroy. I have started to water it. Ive not noticed any other damage or splits in the main trunk. Is it a crab apple ? If may cut it down come autumn and get something.g productive in there .