1 Planning law based on European legislation is unlikely to change very soon.
The proposed bill to allow the scrapping of elements of European Union laws that the government does not want to keep will only take effect on Brexit day, two years after the government triggers the UK’s exit from the EU, said planning barrister Richard Humphreys QC of No5 Chambers.
Even then, disentangling the parts of the EU law that it wants to keep will be "a huge task", he said. This means that "it is likely that most existing European law will remain UK law on Brexit day, and over time relevant parts will be repealed," he said.
"There is not going to be an immediate bonfire of regulation".
2 But the application of some of those laws might be altered by the UK’s departure from the European Union.
Humphreys suggested that UK courts could start to interpret the some planning-related laws differently after Brexit.
He gave the example of the Conservation of Habitats and Species Regulations 2010, which transposed a European directive.
The regulations say that, if development is "likely" to have an impact on a site designated under a European conservation classification, then the competent authority has to assess the extent of the impact.
Ever since a European Court of Justice ruling in 2005, the courts have interpreted "likely" as meaning that the risk that the development might have such an impact "cannot be excluded", Humphrey said.
But, after Brexit day, he said the UK courts would be free to reconsider whether such an interpretation accorded with normal English language usage, in which "likely’ tended to mean "more likely than not".
3 Transport infrastructure projects that would have been supported by European treaties could be called into question.
Infrastructure schemes such as HS2, the northern rail hub and the A14 trunk road improvements helped the UK government to meet its treaty commitments to promote trans-European networks, Bartlett School of Planning visiting professor Janice Morphet told delegates.
Equally, the treaties helped provide the legal basis for these schemes, and ensured that they were a priority for UK government and European funding.
Once the treaties are annulled, some of these projects would have "no anchor", she said. "A particularly litigious objector could ask what this project rests on".
Conference chair Duncan Sutherland, a board member of the company set up to deliver HS2, questioned the extent of the danger to a project like HS2 "which had been through a four year parliamentary procedure".
Whether or not the change would undermine existing infrastructure projects, said Morphet, it would require a change in the way that future such projects were planned.