Do you remember what the presumption of ad medium filum means? The answer is that when land abuts a highway (or private right of way), the boundary of that land is presumed to extend to the middle of that right of way (or highway). 


In practice, the presumption is very rarely required these days since, in the majority of cases, it may be that the owner of the land adjoining the highway has no interest in proving its claim to that part of the highway. However, in cases where a highway is subject to a stopping up order, or where closing orders have been made that extinguish rights of way leading to it, it may be that the presumption will be of more use. Moreover, in the case of a private road over which private rights of way may have been acquired, there may be an advantage to the owner of adjoining land to claim ownership ad medium filum in order to challenge the rights of its neighbour to use the route (eg if the neighbour cannot prove sufficient use to establish rights by prescription or lost modern grant). 


Remember it is only a presumption and, as was said in Pryor [1894] it is ‘a curious legal inference, and an inference that is capable of being rebutted by circumstances which show that the parties never really intended the omitted land to pass’. Source: [2010] 260 PLJ 16.