Mandatory vs discretionary grounds: what's the difference?

Every Section 8 ground for possession falls into one of two categories, and the difference matters a great deal for how confident you can be about the outcome of a possession claim.

Mandatory grounds

Mandatory

If you can prove a mandatory ground applies, the court has no discretion — it must grant a possession order. This doesn't mean it's automatic or effortless: you still need to serve the correct notice, give the right amount of time, and prove the ground genuinely applies at the court hearing. But once proven, the court can't refuse possession on the basis that it doesn't seem fair or reasonable in the circumstances.

Rent arrears at the mandatory threshold, a landlord or family member needing to move in, and selling the property are all examples of mandatory grounds.

Discretionary grounds

Discretionary

With a discretionary ground, proving the ground is only the first step — the court then has to separately decide whether it's actually reasonable to grant possession, taking the full circumstances into account. Two cases with identical facts on paper can have different outcomes depending on how the judge weighs the wider situation.

Lower-level rent arrears, persistent late payment, breach of tenancy terms, and general antisocial behaviour are common examples of discretionary grounds.

Why this distinction matters in practice

• Certainty — mandatory grounds give you a much clearer sense of the likely outcome if the facts are proven, which matters if timing or certainty is important to you.
• Strategy — it's common, and allowed, to rely on more than one ground at once. Pairing a discretionary ground with a mandatory one as a backup is a standard approach if you're not entirely sure the mandatory threshold will be met by the time of the hearing.
• Evidence — discretionary grounds generally benefit from a fuller evidence picture, since the court is weighing reasonableness, not just checking a box.

A common misunderstanding worth clearing up

Mandatory doesn't mean guaranteed, and discretionary doesn't mean weak. A mandatory ground that isn't properly proven at the hearing — for example, rent arrears that have dropped below the threshold by the court date — will fail just as surely as a discretionary ground the court decides isn't reasonable to act on. The label describes the court's power once the ground is proven, not how easy it is to prove in the first place.