This is the case of the lad who arrived on the back of a lorry with no documents, money or anywhere to go and was assessed as being a man in his 20s rather than the 15 year old he claimed to be.
The Court decided that he had been falsely imprisoned for a period of 44 days. Additionally the Home Secretary was found, by proxy, to have breached the boy's Article 5 European Convention on Human Rights (ECHR) rights to liberty and security. The key elements of the decision appear to be -
"66. The Defendant submitted that an immigration officer who was exercising the power of detention was in an analogous position to that of a police officer having reasonable grounds on which to arrest, or the hospital trust admitting the patient on the basis of an application which appeared to be in order.
67. I do not consider that it is permissible to extend the powers of an immigration officer to detain in this way in the absence of express provision. In reaching that conclusion, I rely upon the well-established common law principle that "the right to liberty is of fundamental importance and that the courts should strictly and narrowly construe general statutory powers whose exercise restricts fundamental common law rights and/or constitutes the commission of a tort": per Lord Dyson in R (Lumba) v Secretary of State for the Home Department  1 AC 245, at …
Grounds of challenge to the legality of detention
(1) Age Assessment
113. In this case, Ms Noons said in evidence that she did not see it as her role to check whether or not the assessment was Merton-compliant. Indeed, she candidly admitted that she did not know what the Merton criteria were, and I concluded that she did not have the requisite training to decide whether or not the assessment was Merton-compliant. I accept the Claimant's submissions that, on the evidence, Ms Noon's decision to detain was unlawful because she failed to ask herself the right questions or take reasonable steps to acquaint herself with the information needed to make her decision. She did not follow the EIG policy and UKBA Guidance which I have referred to above. It was clear from the face of the assessment that there was no appropriate adult present; that it had been signed by only social worker; and that there were no comments by the Claimant on the social worker's adverse findings. This should have prompted Ms Noons to make further enquiries of the local authority. If she had done so, it could have become apparent at a much earlier stage that the local authority assessment was not Merton compliant, as was subsequently conceded by the local authority. …
(2) Section 55, Borders, Citizenship and Immigration Act 2009
130. My conclusion is that, by failing to have regard to the need to safeguard and promote his welfare as a child, the immigration officers erred in law, rendering the decision to detain unlawful.
3) Article 5 ECHR
142. In this case, it is established on the evidence that the Defendant, when detaining the Claimant: a) failed to have regard to his best interests as a child, contrary to Article 3 UNCRC;
b) detained him with adults and failed to consider an alternative to detention, contrary to Article 37 UNCRC.
143. Therefore I conclude that the Claimant's detention was in breach of Article 5(1) ECHR, and hence unlawful under s.6(1) HRA 1998.
(4) Detention in breach of policy and Hardial Singh principles
… 160. I accept that there was administrative delay in conducting the Claimant's initial screening interview. But in my view his detention was not unlawful, applying Hardial Singh principles. The purpose for which he was being detained was to obtain the necessary information to decide whether leave to enter should be granted or refused. The period of detention was reasonably necessary to achieve that purpose, taking into account the particular circumstances of his case, namely, that he was not eligible for the fast track process nor for Oakington. In my view, the Defendant acted with reasonable diligence and expedition. I do not consider that the delay in transferring the file, and the failure to meet the benchmark for conducting a screening interview, were sufficiently serious failings so as to justify a finding that detention was unlawful on Hardial Singh grounds. For the same reasons, the length of detention did not breach Article 5, as it did not "exceed that reasonably required for the purpose pursued" (Saadi, at ) nor did it breach paragraph EIG 55.1.3.
161.For the reasons set out above, the Claimant's detention was unlawful, and therefore he was falsely imprisoned for a period of 44 days. 162. The Claimant's detention was also in breach of Article 5 ECHR and the Human Rights Act 1998."