Yesterday the government launched a consultation on changing the thresholds above which rail and highway projects are considered nationally significant.  The consultation paper is here.

These are the third and fourth consultations on altering thresholds: the government has previously consulted on and introduced a threshold for waste water transfer and storage, and recently carried out a consultation on varying the electric line threshold.

Rail threshold

The rail threshold at the moment is hardly a threshold at all.  If a rail project would involve construction outside the original railway boundary, then it cannot rely on 'permitted development' rights and so must be authorised under the Planning Act.  The original railway boundary is set out in the plans associated with the usually 19th century Act of Parliament when the railway was first authorised - not the most accessible document.

The consultation is about whether to introduce a minimum length, and 2 continuous kilometres of new railway outside the boundary is suggested.  'Continuous' means that if the new railway goes in and out of the original boundary but is never out for more than 2 km at a time, then it would not need authorisation under the Planning Act.

Highway threshold

The highway threshold is already the longest in terms of number of words to describe it in the Planning Act.  The consultation proposes to make it even longer, with four proposed changes, so wrap a damp towel around your head and read on.

First, the construction of roads where the local authority will be the highway authority is to be removed altogether.  All that worry about what 'a purpose connected with' means will disappear.

That leaves trunk roads and motorways.  The second change is where these are to be constructed as necessary mitigation for a developer's project.  If the developer's project (i.e. such as housing, commercial or mixed use) has planning permission, then the developer would not need to use the Planning Act for the highway works.

That leaves non-developer-prompted trunk roads and motorways.  The third change is that for those that have existing Highways Act orders that are less than seven years old, but these need to be changed, then the Planning Act does not need to be used.

That leaves not recently authorised non-developer-prompted trunk roads and motorways.  The final change is to introduce a size threshold for the remaining schemes.  Rather than a length threshold, though, it is to be an area threshold depending on the proposed speed limit for the new road.  If it is to be a motorway, then the threshold is 15 hectares; if the speed limit will be 50mph or more it is to be 12.5 hectares and if it is to be less than 50mph then it is to be 10 hectares.


I feel a bit got at by this consultation since I or my colleagues are acting on most of the projects mentioned that would no longer need to use the Planning Act.  But hey, if that's the price of encouraging growth, so be it - growth equals more projects equals more work.  I will now analyse the changes while trying not to be too biased.

A length threshold for railways seem sensible, although the 2 continuous kilometres test will still mean dusting down the old plans. 

The proposed highway changes are worthy of more comment. Removing construction of local authority roads altogether is likely to appeal to local transport authorities, but I would have thought that some larger local authority schemes would fulfil the ordinary meaning of 'nationally significant'.  My initial feeling is that this change goes too far in the other direction and that the largest local authority schemes that are nationally significant still ought to have to use the Planning Act regime.

Schemes whose sole purpose is to connect developer projects to the road network and where the nearest main road happens to be a trunk road are highly unlikely to be nationally significant in the ordinary sense.  It is sensible that the threshold is clarified to remove these.  It gets more complicated if a road will partly mitigate a developer scheme but also be used by drivers not visiting the development - should these have to use the Planning Act or not?  Also, timing issues may mean that a developer wants to apply for the highway before getting planning permission for the main development, so some projects of this type may still end up using the Planning Act.

Schemes where orders have already been made under the Highways Act but need to be changed are barely mentioned in the consultation and aren't the subject of a direct consultation question.  This change will allow one or two particular schemes to avoid the Planning Act (and I think I know which one this is intended to benefit, but far be it for me to say which it is), but will become of less use over time and will become ineffective on 1 March 2017.

Introducing an area threshold seems rather counter-intuitive. As a rule of thumb, if the land needed for a motorway was 100 metres wide, then this would correspond to 1.5km of motorway.  Slower roads are likely to be narrower, which means that the length is likely to work out at about the same, so why not just have a length in the first place?  The impact assessment included with the consultation says that a large motorway junction might not trigger a length threshold and yet be of national significance.  The government also considered a scheme cost threshold but thought that might be too difficult to define.

Promoters of schemes that will fall below the threshold will still have the option of applying to use the regime if they think that will suit them better.  Those who have already applied under the Planning Act will be unaffected, and the consultation asks what to do about those that have taken some steps short of an application.


The consultation is open until 22 January, and the changes are expected to be implemented in June.  The wording of the changes will be quite important and this is not fully set out in the consultation.  I would expect draft legislation to appear in late April or early May.