The fallback argument and how inspectors test it

A fallback position in a planning appeal carries weight only where the inspector accepts that the alternative development has a real prospect of being carried out. That is the test, and it is lower than probability. The Court of Appeal in Mansell v Tonbridge and Malling Borough Council [2017] EWCA Civ 1314 confirmed that a decision maker may treat a fallback as a material consideration without being satisfied that it is more likely than not to happen. What the argument cannot survive is being merely theoretical.

So the drafting task is evidential rather than rhetorical. Establish what could lawfully be built or done if the appeal fails, establish why your client would do it, then compare the planning consequences of the two outcomes.

What the argument actually claims

A fallback argument says: refuse this and something else happens instead, and that something else is worse, or at least no better. It is a comparative exercise. The appeal scheme is measured against a realistic alternative rather than against an empty site or an undisturbed status quo.

Two things follow. First, the fallback must be lawful without the permission under appeal, whether through permitted development rights, an extant planning permission, an existing lawful use or works that fall outside section 55 of the Town and Country Planning Act 1990. Second, somebody must be able and willing to implement it.

Agents often get the first part right and skip the second. An inspector who is handed a set of permitted development drawings and nothing else will usually record that the fallback is possible in law and then give it little or no weight.

The real prospect test

Mansell is the case to cite, and it rewards being quoted accurately. Lindblom LJ described the question as whether there is a real prospect of the alternative being implemented, which leaves the decision maker a wide margin of judgement on both the existence of the prospect and the weight it attracts. Those are two separate findings. An inspector can accept that a fallback exists and still conclude that the weight is limited because the alternative is unattractive to the owner.

That second finding is where most fallback cases are lost, and it is the one agents spend least time on.

Weight tends to rise with commercial logic. A fallback that the owner would plainly prefer to doing nothing, that costs less than the appeal scheme, and that delivers an outcome the owner has already pursued elsewhere, reads as real. A fallback nobody would ever build reads as a device.

Evidence that the fallback would be implemented

Treat this as a short evidence chapter in the statement of case rather than a paragraph. What persuades:

• A lawful development certificate under section 192 of the 1990 Act, or a prior approval already granted, which removes any argument about whether the alternative is lawful.
• Drawings of the fallback to the same standard as the appeal drawings, so the comparison is like for like.
• A costed build-up showing the fallback is financially deliverable, with a signed statement from the client confirming the intention to proceed if the appeal fails.
• Evidence of steps already taken, for instance a building control application, a contractor appointment or a demolition quotation.
• Where the fallback relies on an extant permission, confirmation that it has been lawfully implemented or that the time limit has not expired.

A witness statement from the client saying the fallback will be built, with nothing behind it, is the weakest version of this. Inspectors read a great many of them.

Comparing harm between the fallback and the appeal scheme

Once the prospect is accepted, the comparison needs to be structured by issue rather than asserted in the round. Take the reasons for refusal in turn and set the fallback against the proposal on each. Where the refusal notice cites neighbour amenity, that means daylight, outlook, privacy and noise separately, not "amenity" as a single heading. Our note on reading a refusal notice and turning it into a plan covers how to break a notice down for this purpose.

A short table does the work better than prose:

Be honest where the fallback is better on an issue. An inspector who finds one overstated line will discount the rest. And a fallback that is worse on three issues out of five is still a useful argument, provided the overall balance is drawn carefully. Amenity comparisons in particular need the numbers set out, which is where our piece on neighbour amenity refusals is relevant.

Fallbacks that rest on permitted development

Householder and agricultural appeals lean on this most. The attraction is obvious: Schedule 2 of the Town and Country Planning (General Permitted Development) (England) Order 2015 gives a dimensioned alternative with no design control attached to it.

The traps are procedural. Check whether an Article 4 direction has removed the class. Check the cumulative limits, because Class A for a dwellinghouse counts earlier enlargements and the position depends on what was there on 1 July 1948 or on the original build. Check the conditions in A.1 and A.2, especially the materials condition and the restrictions that apply on Article 2(3) land. A fallback built on a misread of the GPDO collapses the whole argument, and the inspector will say so in a sentence.

Where the permitted development route needs prior approval under Part 1 for a larger rear extension, or under Part 3 for a change of use, the fallback is contingent. That is survivable, but the statement should say plainly that prior approval would be sought and why it would be granted.

This is general guidance rather than legal advice, and permitted development rights vary by site and by designation. A lawful development certificate is the only formal way to confirm that works are lawful, so for anything marginal, apply for one.

Fallbacks that rest on an extant permission

An unimplemented permission with time left on it is the cleanest fallback available, because lawfulness is not in dispute. The questions become expiry and viability. Confirm the date any works began, whether conditions require approval before a start on site, and whether the permission has been lawfully begun under section 56.

Where a permission has been begun through a material operation, it survives indefinitely, and that strengthens the case considerably. Where a start on site is months away and conditions remain undischarged, expect the inspector to probe the programme.

Sometimes the better course is to withdraw and resubmit rather than argue the point at appeal, and our note on withdrawing an application before refusal sets out when that is worth doing.

Where inspectors dismiss it

Four patterns recur in decisions. The fallback is unlawful on examination. The fallback is lawful but nobody would build it, usually because it produces a worse house or a smaller unit than the owner wants. The comparison is asserted without drawings. Or the fallback would itself cause the harm the council identified, so the comparison proves nothing helpful.

There is also a limit of principle. A fallback cannot make acceptable a scheme that conflicts with the development plan on its own terms, because section 38(6) of the Planning and Compulsory Purchase Act 2004 still requires the determination to be made in accordance with the plan unless material considerations indicate otherwise. The fallback is one of those considerations, weighed against plan conflict rather than replacing it. Objectors will make that point, and they are entitled to be heard on it, as our note on what objectors can do once a planning appeal starts explains.

Put the fallback in the Planning Statement at application stage rather than saving it for the appeal. An officer who has seen the comparison and rejected it gives you a cleaner record to appeal against than one who meets it for the first time in a statement of case.

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