Yes, under the terms of the Trust Act 1925, trustees can be removed for a number of reasons, including if they:
Request to be removed
Have passed away
Remain outside of the UK for more than a year
Refuse to carry out their role
Are unfit to carry out their role
Are incapable of carrying out their role (e.g. through illness or incapacity)
Are under the age of 18
An application will need to be made to a court to have the trustee removed.