💡 The right to privacy is not officially established in the UK even after ECHR. It only became effective when HRA 1998 (i.e., incorporated into UK's legislation) was passed.
The concept of privacy is first associated with the right to not be forced against their will in their house (similar to U.S. Fourth Amendment - illegal search and seizure)
“The house of every one is his castle and fortress, as well for his defences against injury and violence, as for his repose…” – at p.1 Peter Semayne v Richard Gresham 77 ER 194
💡 Did you know that the US does not have explicit protection of privacy right in their constitution? Instead, the U.S. Amendments (e.g., First, Third, Fourth, Fifth, etc.) imply this right.
Prince Albert v Strange (1849) 41 ER 1171
"privacy is the right invaded" - this makes privacy a standalone right
but doesn't it set a base on another substantive right - e.g., right to marriage? (read to learn more)
Coco v A.N. Clark (Engineers) Ltd  FSR 415
case on confidence (i.e., confidential information)
❓ but what if an individual wishes to protect their privacy but is absent of an associated cause of action? or current cause of action is ill-fitted?
Kaye v Robertson  EWCA Civ 21
photos taken of a celebrity being hospitalized by the press and about to publish - is it an invasion of privacy?
hence, if Person A is in absence of a right (e.g., confidence), A can sue for:
trespass to person
passing off - on unregistered trademarks, protect the goodwill of the trader from misrepresentation
R v Director of Serious Fraud Office, ex parte Smith  AC 1
balancing privacy and other basic rights (e.g., freedom of speech)
[It] is a simple reflection of the common view that one person should so far as possible be entitled to tell another person to mind their own business. All civilised state recognize this assertion of personal liberty and privacy. Equally, although there may be pronounced disagreements between states, and between individual citizens and states, about where the line, few would dispute that some curtailment of liberty is indispensable to the stability of society...
Article 8 of HRA 1998
"right to respect for his private and family life, his home, and his correspondence"
public authority can only interfere under stated special circumstance: "accordance with law", "necessary in a democratic society in the interests of national security, public safety..."
❓Why is the Human Rights Act, as well as the European Court of Human Rights (ECtHR) needed in the UK? Doesn't it lead to 'judicial tyranny' and over-interference with the public administration?
This misconception here is that 250 years of common law is being displaced by Human Rights Act. However, in practice, there have been many cases in which UK courts ruled on the basis of common law. For instance, a case (The Queen on the application of Privacy International v. Investigatory Powers Tribunal) ruled by the Supreme Court in 2019 based its focus on public law jurisprudence. In addition, ECtHR will rarely try issues that have not exhausted the domestic courts. For instance, Privacy International and Others v. United Kingdom (2020) was rejected by ECtHR on the basis that domestic remedies are not being exhausted.
Douglas v Hello! Ltd  2 WLR 992
freedom of expression vs right to privacy: claimant sought an injunction to prevent photos of their marriage (without their consent and under private occasions) from being published
"right to freedom of expression...is a powerful card to which the courts of this country must always pay proper respect" as being written in Section 12 (3) of HRA: "No such relief is to be granted so as to restrain publication before trial unless the court is satisfied that the applicant is likely to establish that publication should not be allowed."
respondent has to prove, by a reasonable standard, that the thing in dispute [here, publication of photos] is of public interest
Fact sensitive approach: Douglas and Zeta-Jones' rights are not enough to permit injunction due to their roles as public figures - impactful to celebrities who are commercializing part of their privacy
❓ What are the levels of review in the UK?
💡 Wednesbury unreasonableness - targeting governmental decisions that are "so absurd that no sensible person could ever dream that it lay within the powers of the authority" with different levels of scrutiny (anxious-scrutiny to 'light touch')
After the establishment of HRA, persons are able to bring to domestic court infringement of their ECHR rights. This helps courts to scrutinize the invaded fundamental rights and provide greater protection for them.
R v. Ministry of Defence, ex parte Smith : "[t]he more substantial the interference with human rights, the more the court will require by way of justification before it is satisfied that the decision is reasonable"
❓ Comparison of intermediate scrutiny in the US and anxious-scrutiny in the UK。
The similarities between them are the proof of burden on the public authority. The difference is the scope of protection (subject to change).
many of its right and liberty (e.g., Fourth Amendment) is being protected by intermediate scrutiny
Government must prove that the law must further a governmental interest and must do so in methods that substantially related with the interest.
The term "anxious scrutiny" originated from R. v. Secretary of State for the Home Department, ex parte Bugdaycay (1986),:
"The most fundamental of human rights is the individual's right to life and when an administrative decision under challenge is said to be one which may put the applicant's life at risk, the basis of the decision must surely call for the most anxious scrutiny".
However, after HRA, the judiciary has been adopting a similar approach as what Lord Bridge implied - "rights-based approach" - to its other fundamental rights.
A question worthy to look into:
Why is intermediate scrutiny (i.e., reasonable standard) used rather than strict scrutiny? Isn't the right to privacy a fundamental right as well?
Campbell v MGN 
provided a two-stage test for inappropriate use of private information:
if the individual had a reasonable expectation of privacy (claimant's attributes, nature, place, effect, etc.)
weighing privacy rights with other interests (comparison is rather relative and based on context)
"Very often, it can be expected that the countervailing rights of the recipient will prevail.”
Campbell prevailed as the release of this sensitive issue will lead to the risk of damages to both Campbell and potential victims.
Mosley v News Group 
the appellate court decides on the proportion as well as whether "breach of privacy was qualified as a tort"
ACPO Guideline and PACE ("Samples")
concerned of fingerprints and retention of data
need to be justified as a proportionate means to achieve a legitimate aim of crime prevention (which meant enabling judicial review over public authorities)
An informal summary of "A brief introduction to the concept of privacy under English law", which is written by The Privacy Perspective, along with my own thoughts as well as my questions and findings.