Thanks for your question.
You have a right to a property in repair and free from damp mold, if the property is unfit for human habitation then you will be able to terminate the agreement.
If you suspect you have mold but are not sure and they have not completed a thorough check then I would pay to get a professional rounds to look, if he find mould you will be eventually able to reclaim the expense from your landlord.
If the state of the mold (particularly damp) is very bad then you should contact the local authority environmental health department and ask them to send an officer round. If the state of the property is bad he will issue an enforcement notice against the Landlord to carry out works and this may prompt him in to making the repair. If he finds it unfit for human habitation then he will declare it as such and you will be able to terminate your agreement with the landlord on the basis of this breach.
Whilst doing the above you should formally write to the the landlord specifying the disrepair, making a list of the reasonable repair required and ask that he make those repairs within a reasonable time (eg. 7 days). State that if the landlord does not make the repair within that time you will pay to have the repairs made and will seek to claim the expense from him and are prepared to make an application to court if necessary.
If the landlord does not make the repair you can pay to have it done and then write formally to him requesting the payment of the cost, again within a reasonable time). If he does not pay you can issue a claim for the money yourself through Her Majesty Courts Service's online service: www.moneyclaim.gov.uk
If the severity of the damp is very bad then you can ask to be rehoused by them, with them paying the expenses until the damp has been sorted out.
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