In A Local Authority v SY  EWHC 3485 (COP) Keehan J found that
TK exploited and took advantage of SY for the purpose of seeking to bolster his immigration appeal and his prospects of being permitted to remain in this country. The ceremony he and SY engaged in on 10 June 2012 formed the bedrock of that objective.
TK well knew that SY had learning difficulties and was a vulnerable young woman. He knew that the police and the care services were extremely concerned about his involvement with SY.
I can reach no other conclusion than he deliberately targeted SY because of her learning difficulties and her vulnerability. The courts will not tolerate such gross exploitation.
Fortunately, it would appear that TK's involvement in SY's life is not now causing her emotional distress or harm. It was, however, yet another abusive and exploitative episode in her life which could have had serious physical, emotional and psychological consequences for her. In my judgment it is important for SY that a declaration of non-marriage is made in respect of the June 2012 ceremony. There are also, in my judgment, compelling reasons of public policy why sham 'marriages' are declared non-marriages. It is vital that the message is clearly sent out to those who seek to exploit young and vulnerable adults that the courts will not tolerate such exploitation.
It is plain from all of the evidence before me that SY lacks the capacity to litigate and the capacity to make decisions about her residence, her contact with others, her care package and to enter a contract of marriage. I find the care package proposed by the authority and the orders sought are in SY's best interests. Accordingly, I make all of the orders sought.
I am satisfied that, on the facts of this case, the appropriate and proportionate course is for the court, of its own motion, to invoke the inherent jurisdiction of the High Court and to make the declaration that the ceremony in which SY was involved on 10 June 2012 was a non-marriage.TK man had arrived in the UK from Pakistan to study in 2009 but his application to stay was refused after an immigration tribunal concluded he had submitted forged documents and attempted to deceive officials. TK's rights of appeal regarding that refusal were exhausted in June 2011. In August 2011, pending deportation, he began a relationship with SY. She is "a 19 year old young woman who has mild to moderate learning disability and is extremely vulnerable". SY, with an IQ of 49 and a history of involvement with welfare authorities, was held to lack capacity to litigate. She was also held to lack capacity to make decisions regarding her residence, the contact she should have with others, the care package she should receive, and entering into a contract of marriage.
On 23 January 2012 her then carers notified the authority that she had returned from TK's property in a nearby city and told them that TK had locked her in his house when he went to work, she and TK had been visited by a 'lawyer' about a housing application, that they were to marry in six months time and that TK had taken her to a registry office to obtain a copy of her birth certificate. The carers reported they had overheard TK speaking to SY on the telephone in a controlling and aggressive manner. ...
On 24 May 2012 the authority and the police told TK that SY had a learning disability and was unlikely to have capacity to consent to sexual relations and marriage and that an offence would be committed. Notwithstanding this advice, on 10 June 2012 TK and SY entered into a purported Islamic marriage ceremony at his home. ...
On or around 15 June 2012 TK was arrested for immigration offences and detained by the UK Border Agency pending his deportation. He claimed asylum on the basis that he feared he would be killed by his family who disapproved of his marriage to a white British woman, namely SY. …
On 17 July 2012 TK's appeal against the refusal to grant him asylum was dismissed on all grounds. His relationship with SY lay at the heart of the case he sought to mount. The tribunal judge found that "The relationship, if there is one, does not have the necessary qualities of commitment, depth and intimacy which would be necessary to demonstrate family life for the purposes of article 8 …". He later observed that "viewed objectively her best interests are likely to be served by there being no further interference by [TK] and his friends with the care arrangements which social services have put in place". He was found not to have given a truthful account in his evidence and not to be a credible witness.There is a similar exploration of capacity in YLA v PM & Anor  EWHC 4020 (COP)