Damp is commonly caused by issues affecting the property itself such as rising damp, water leaks and water ingress. This being said, many instances of mould growth are as a result of condensation. Of course it is the tenant’s responsibility to ensure that your property is well ventilated, adequately heated and is as free from clutter as is practicable. This being said, condensation associated mould is frequently caused by issues beyond the control of the tenant, which could be made significantly worse by problems for which the Landlord has responsibility for, e.g. defective extractor fans/heating.
If damp and mould is not addressed adequately and within a reasonable time after you have given notice, this could have a consequence of allowing your home to uninhabitable. It is a vital importance that you notify your Landlord of the existence of damp and/or mould at the earliest opportunity.