How to fix failed removal of partition.

I tried installing bootcamp then got stuck and gave up. I then tried to remove the bootcamp partition, but an error message came up during the process and said there was an error removing the partition. The programme ended up closing and now I am left with an empty partition which I can't figure out how to delete.
–As you can see in the image above, the partition doesn't have an option to erase.
–On my bootcamp helper, the option to 'Remove existing partition' is now replaced with the standard 'Install bootcamp partition'

Any thoughts on how to fix this?

Macbook Pro Late 2011 Yosemite

Thanks in advance,

Sam