The decision of the House of Lords in London Borough of Lewisham v Malcolm [2008] UKHL 43, [2008] 4 All ER 525, made it significantly more difficult for a disabled tenant to argue that his landlord had discriminated against him on the grounds of ­disability.

Mr Malcolm was a secure tenant of the council.

He had schizophrenia and was a disabled person for the purposes of the Disability Discrimination Act 1995 (DDA), although the council was unaware of this.

When Malcolm sublet his flat in breach of his tenancy agreement the council sought to evict him on the basis that his secure tenancy had come to an end.

Malcolm contended that, because of his disability, he did not understand that he could not sublet his flat and that the council’s attempt to evict him amounted to disability discrimination in breach of section 22(3) of the DDA.

The House of Lords, overturning the Court of Appeal, ruled that discrimination under the DDA required the landlord to have a subjective knowledge of the disability, and the majority held (Baroness Hale dissenting on this issue) that the treatment of Malcolm had to be compared with that of a tenant who had sublet but who did not have a disability.

This meant that Malcolm would have had to show that a non-disabled tenant who had sublet was treated better and had not been, or would not be, evicted.

The House of Lords found that the council would have sought possession against any tenant who had sublet unlawfully and that Malcolm had not therefore been treated less favourably for a disability-related reason.

The comparator constructed by the House of Lords in Malcolm overturned a longstanding Court of Appeal decision in the employment case of Clark v TDG Limited t/a Novacold [1999] ICR 951, [1999] 2 All ER 977, which had alleviated the burden of showing that a person had been treated less favourably for a reason related to his disability.

The effect of the decision in Malcolm was regarded as restricting the wider purpose of the DDA to provide protection from disability-related discrimination.

As a consequence, section 15 of the Equality Act 2010 (EA) was enacted specifically with the intention of ‘re-establishing an appropriate balance’ between the rights of disabled people and the interests of those with related duties.

Section 15(1) provides that a person (A) discriminates against a ­disabled person (B) if A treats B unfavourably because of something arising in consequence of B’s disability and A cannot show that the treatment is a proportionate means of achieving a legitimate aim.

Hence the requirement for a comparator has been removed.

However, the requirement of knowledge of the disability, whether actual or constructive, has been retained at section 15(2) of the EA.

Therefore, a landlord will have a defence to a claim for discrimination under section 15 if he can show that he did not know, and could not reasonably have been expected to know, that the tenant had a disability.

It remains to be seen whether the phrase ‘because of something arising from B’s disability’ is susceptible to a wider interpretation than the wording of section 3A of the DDA (‘for a reason which relates to the disabled person’s disability’) which it supplanted.

In Malcolm, Lord Scott considered the circumstances in which something could be said to relate to a person’s disability.

He referred to the hypothetical case of a blind man with a guide dog who wished to enter a restaurant which did not permit the entry of dogs.

His lordship stated that since a blind man without a dog would not have been refused entry ‘the problem was the dog’.

Since the dog was the reason for the refusal of entry this was not related to the blind man’s ­disability.

Would Lord Scott’s restaurant owner benefit from a similarly narrow interpretation of section 15 of the EA?

This would not be parliament’s intention and, in any event, the possibility now exists that there would be a finding of indirect discrimination in such circumstances, because although section 19, which defines indirect discrimination for the purposes of the EA, largely replaces similar provisions in previous legislation, it now extends indirect discrimination to disability.

This was a further consequence of the consultation which resulted from the decision in Malcolm.

Indirect discrimination occurs when a policy which applies in the same way for everybody has an effect which particularly disadvantages people with a protected characteristic.

Where a particular group is disadvantaged in this way, a person in that group is indirectly discriminated against if they are put at that disadvantage, unless the person applying the policy can justify it.

Hence it could be argued that a policy of excluding dogs from restaurants has the effect of disadvantaging blind people who have guide dogs.

Furthermore, prior knowledge of a person’s disability, or the lack of it, is immaterial to a finding of indirect ­discrimination.

So would the EA have provided Malcolm with a successful defence to his landlord’s claim for possession?

The answer is probably not, because the landlord’s lack of knowledge of his disability would still be a material factor in considering whether he had been discriminated against in breach of section 15.

However, if the landlord had known of the disability, the claim for possession would undoubtedly have failed.

It is not difficult to envisage other situations in which a claim for possession against a disabled tenant could be defeated by a defence based on section 15 or, in certain circumstances, section 19.

Imagine, for example, a claim based on rent arrears which have arisen because a tenant lacking mental capacity is unable to manage his financial affairs (see S v Floyd and the Equality and Human Rights Commission [2008] EWCA Civ 201, [2008] 1 WLR 1274), or a claim based on nuisance where the tenant’s behaviour is attributable to mental illness (see Manchester City Council v Romano [2004] EWCA Civ 834, [2004] 4 All ER 21, and also Barber v Croydon London Borough Council [2010] EWCA Civ 51, [2010] The Times 24 March).

The message to any landlord who is seeking to recover possession from a tenant with a disability is clear: proceed with caution.

District Judge Michael Anson sits at Preston County Court