But liability should only be imposed under this principle in cases where [...]. Moreover, it is not to be forgotten that, in ordinary households in this country, there are nowadays many things which might be described as possible sources of fire if interfered with by third parties, ranging from matches and firelighters to electric irons and gas cookers and even oil-fired central heating systems. These are commonplaces of modern life; and it would be quite wrong if householders were to be held liable in negligence for acting in a socially acceptable manner. No doubt the question whether liability should be imposed on defenders in a case where a source of danger on his land has been sparked off by the deliberate wrongdoing of a third party is a question to be decided on the facts of each case, and it would, I think, be wrong for your Lordships' House to anticipate the manner in which the law may develop; but I cannot help thinking that cases where liability will be so imposed are likely to be very rare.
There is another basis on which a defender may be held liable for damage to neighbouring property caused by a fire started on his (the defender's) property by the deliberate wrongdoing of a third party. This arises where he has knowledge or means of knowledge that a third party has created or is creating a risk of fire, or indeed has started a fire, on his premises, and then fails to take such steps as are reasonably open to him (in the limited sense explained by Lord Wilberforce in Goldman v Hargrave [1966] 2 All ER 989 at 995–996, [1967] 1 AC 645 at 663–664) to prevent any such fire from damaging neighbouring property. If, for example, an occupier of property has knowledge, or means of knowledge, that intruders are in the habit of trespassing on his property and starting fires there, thereby creating a risk that fire may spread to and damage neighbouring property, a duty to take reasonable steps to prevent such damage may be held to fall on him.

But liability should only be imposed under this principle in cases where [...]. Moreover, it is not to be forgotten that, in ordinary households in this country, there are nowadays many things which might be described as possible sources of fire if interfered with by third parties, ranging from matches and firelighters to electric irons and gas cookers and even oil-fired central heating systems. These are commonplaces of modern life; and it would be quite wrong if householders were to be held liable in negligence for acting in a socially acceptable manner. No doubt the question whether liability should be imposed on defenders in a case where a source of danger on his land has been sparked off by the deliberate wrongdoing of a third party is a question to be decided on the facts of each case, and it would, I think, be wrong for your Lordships' House to anticipate the manner in which the law may develop; but I cannot help thinking that cases where liability will be so imposed are likely to be very rare.
There is another basis on which a defender may be held liable for damage to neighbouring property caused by a fire started on his (the defender's) property by the deliberate wrongdoing of a third party. This arises where he has knowledge or means of knowledge that a third party has created or is creating a risk of fire, or indeed has started a fire, on his premises, and then fails to take such steps as are reasonably open to him (in the limited sense explained by Lord Wilberforce in Goldman v Hargrave [1966] 2 All ER 989 at 995–996, [1967] 1 AC 645 at 663–664) to prevent any such fire from damaging neighbouring property. If, for example, an occupier of property has knowledge, or means of knowledge, that intruders are in the habit of trespassing on his property and starting fires there, thereby creating a risk that fire may spread to and damage neighbouring property, a duty to take reasonable steps to prevent such damage may be held to fall on him.