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Case details

Director of Public Prosecutions (Respondent) v Ziegler and others (Appellants)

Case ID: UKSC 2019/0106

Case summary


In criminal proceedings arising out of protest activity: (1) is deliberate physically obstructive conduct by protesters capable of constituting a lawful excuse for the purposes of s.137 of the Highways Act 1980?; and (2) 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?


The Appellants took part in a demonstration protesting the Defence and Security International weapons fair at the Excel Centre. They were charged with obstructing the highway, contrary to section 137 Highways Act 1980. They were acquitted at Trial because their actions fell within the "lawful authority or excuse" defence contained in section 137 Highways Act 1980. The Director for Public Prosecutions appealed successfully by way of case stated to the High Court. The Appellants now appeal to the Supreme Court.

Judgment appealed

[2019] EWHC 71



Ziegler and others


Director of Public Prosecutions



Lord Hodge, Lady Arden, Lord Sales, Lord Hamblen, Lord Stephens

Hearing start date

12 January 2021

Hearing finish date

12 January 2021

Watch hearing
12 Jan 2021 Morning session Afternoon session

Judgment details

Judgment date

25 June 2021

Neutral citation

[2021] UKSC 23

  • Judgment (PDF) Please note: Line 2, of paragraph 88 in the final approved judgment of Director of Public Prosecutions (Respondent) v Ziegler and others (Appellants) had an incorrect para reference of para 49 when it should have been para 54 – "For the reasons that we have given, we would allow the appeal by answering the certified question set out in para 7(1) as set out in para 54 above". The unreported case of Google LLC v Oracle America, Inc has now been reported in the S Ct Reporter [141 St Ct 1183] and will make it easier for readers to find the case referred to in paragraph 103 of Lady Arden’s judgment.
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  • Judgment on BAILII (HTML version)
Watch Judgment summary
25 June 2021 Judgment summary