This is the wording of the ground
“The condition of the dwelling-house or any of the common parts has deteriorated owing to acts of waste by, or the neglect or default of, the tenant or any other person residing in the dwelling-house and, in the case of an act of waste by, or the neglect or default of, a person lodging with the tenant or a sub-tenant of his, the tenant has not taken such steps as he ought reasonably to have taken for the removal of the lodger or sub-tenant.
For the purposes of this ground, “common parts” means any part of a building comprising the dwelling-house and any other premises which the tenant is entitled under the terms of the tenancy to use in common with the occupiers of other dwelling-houses in which the landlord has an estate or interest.”
Now lets pick it apart.
Basically this ground involves itself with the tenant failing to do something, as opposed to actively damaging the property.
For instance, the ceiling falls in as a result of a leak from the bathroom and the tenant doesn’t report tis disrepair to the landlord.
The problem is, how do you know if the problem is a major structural thing or a trivial decorative matter?
Personally I have the DIY skills of a Labrador. Have a look at the picture below. This is a crack in the plaster in my living room. Does it evidence subsidence or just dry plaster? (its above a radiator). I have no idea. Should I call my landlord?

Would any landlords reading this rather their tenant report every slight issue or just the important stuff? Bearing in mind that DIY numb-nuts like me can’t differentiate between a broken sewer and a bit of condensation.
Neither ‘Defending Possession Proceedings’ the accepted bible on these matters, nor the usual suspect websites offer us much in the way of expansion on the theme.
So basically, all we have to go on here is whether or not the tenant let the property fall into disrepair without telling the landlord.
Clearly some things will be expressly obvious, such as the aforementioned ceiling collapse but not everything will be. I’ve been out on enough site visits with environmental health officers, who know one end of a screwdriver from the other to know that a serious fault isn’t always apparent.
Defending this ground.
Getting into technical land.
Should a tenant report a fault that may be simply minor and decorative in nature?
There will be certain extremes that you can’t defend but there will also be borderline cases of interpretation.
Note from Tessa
Interestingly, in this ground tenants are in effect being held liable for the acts (or failures to act) of their lodgers or subtenants as the ground specifically states that they will be liable if they have not taken ‘reasonable’ steps to remove them.
Note that if the offending person is a lodger or tenant who shares living accommodation, they can do this without getting a court order for possession as this is one of the exceptions in the Protection from Eviction Act 1977.
Any tenant who has lodgers or sub-tenants deserves all they have coming to them.
This in my experience is a very obvious, self evident ground where the tenant was blindingly obvious of a problem they should, as per the agreement, have reported a problem