It is not uncommon for the presence of children in a flat to lead to increased levels of noise for neighbours. However, noise caused by children is a part of ordinary everyday life and, therefore, does not amount to a nuisance. This is the case even if the block has inadequate sound insulation and the disturbance caused to you is worse. You will have an uphill struggle suing for nuisance. To succeed, you will have to show that the parents are not controlling their children’s behaviour and that it is such behaviour (rather than poor insulation) causing unreasonable noise levels in your flat.
Modern leases often have clauses aimed at reducing noise within a block, which can be useful in an action for nuisance. Interestingly, your lease does suggest that residents are intended to enjoy a high degree of protection from noise at night. However, it would be difficult to apply this approach to the daytime.
If negotiation with the relevant parties does not work out, you are in a difficult position. If you start litigation, it may be unsuccessful. You then may feel forced to sell the flat, in which case you will probably have to reveal the fact of litigation to any prospective purchaser, potentially reducing your prospects of a sale. You should consider your options carefully. If you find the present noise unbearable, selling your flat may be the practical solution.
Desmond Kilcoyne is a barrister at 22 Old Buildings, Lincoln’s Inn, and specialises in housing and property law