What is the test to be applied by an appellate court to an assessment of the decision of the trial court in respect of a statutory defence of “lawful excuse” when Convention rights are engaged in a criminal matter?

Analysing Director of Public Prosecutions v Ziegler and others [2021] UKSC 23 case from the perspective of Natural Law

1. In September 2017, the biennial Defence and Security International  arms
fair was held at the Excel Centre in East London. In the days before the opening of
the fair equipment and other items were being delivered to the Excel Centre. The
appellants were strongly opposed to the arms trade and to the fair and on Tuesday 5
September 2017 they took action which was intended both to draw attention to what
was occurring at the fair and also to disrupt deliveries to the Excel Centre.
2. The action taken consisted of lying down in the middle of one side of the dual
carriageway of an approach road leading to the Excel Centre . The appellants attached themselves to two lock boxes with pipes sticking out from either side. Each appellant inserted one arm into a pipe and locked themselves to a bar centred in the middle of one of the boxes.
3. There was a sizeable police presence at the location in anticipation of
demonstrations. Police officers approached the appellants almost immediately and
went through the “5 stage process” to try and persuade them to remove themselves
voluntarily from the road. When the appellants failed to respond to the process they
were arrested. It took, however, approximately 90 minutes to remove them from
the road. This was because the boxes were constructed in such a fashion that was
intentionally designed to make them hard to disassemble.
4. The appellants were charged with wilful obstruction of a highway contrary to
section 137 of the Highways Act 1980 . On 1-2 February 2018, they
were tried before District Judge Hamilton at Stratford Magistrates’ Court. The district judge dismissed the charges, handing down his written judgment on 7 February 2018.
Having regard to the appellants’ right to freedom of expression under article 10 of
the European Convention on Human Rights  and their right to freedom
of peaceful assembly under article 11 ECHR , the district judge found that “on the
specific facts of these particular cases the prosecution failed to prove to the requisite
standard that the defendants’ limited, targeted and peaceful action, which involved an obstruction of the highway, was unreasonable”.
5. The respondent appealed by way of case stated to the Divisional Court, Singh
LJ and Farbey J. Following a hearing on 29 November 2019, the Divisional Court
handed down judgment on 22 January 2019, allowing the appeal and directing that
convictions be entered and that the cases be remitted for sentencing: [2019] EWHC
71 (Admin); [2020] QB 253 . On 21 February 2019, the appellants were sentenced
to conditional discharges of 12 months.
6. On 8 March 2019, the Divisional Court dismissed the appellants’ application for
permission to appeal to the Supreme Court, but certified two points of law of general
DPP v Ziegler, 2021 WL 02592847 .
7. The parties agreed in the statement of facts and issues that the issues in the appeal, as certified by the Divisional Court as points of law of general public importance, are:
(1) What is the test to be applied by an appellate court to an assessment of the
decision of the trial court in respect of a statutory defence of “lawful excuse” when
Convention rights are engaged in a criminal matter?
(2) Is deliberate physically obstructive conduct by protesters capable of
constituting a lawful excuse for the purposes of section 137 of the 1980 Act ,
where the impact of the deliberate obstruction on other highway users is more than
de minimis , and prevents them, or is capable of preventing them, from passing
along the highway?