When a rented property deteriorates or needs repairs so that it is safe and acceptable to live in, it is the responsibility of the landlord to ensure that a basic living standard is maintained.
It is important to know that you do not have the right to simply stop paying rent. However, if you do and your landlord sues you for rent arrears, you can counter-sue for the cost of the repairs which need to be carried out and also for compensation for distress, anxiety and the inconvenience you have suffered.