The British woman who accused a United Arab Emirates senior royal of sexually assaulting her has vowed to fight on after the Crown Prosecution Service declined to prosecute him last month, saying that the CPS decision sends “a clear message to this man and those committing similar crimes that as long as they’re of economic value to the UK, they can do whatever they want”.

Caitlin McNamara, who was the curator of the first Hay festival in Abu Dhabi in February, went public with her accusations last month. She alleges that Sheikh Nahyan bin Mubarak Al Nahyan, the UAE’s minister of tolerance, had attacked her shortly before the festival, which his department had funded. McNamara had believed she would be attending a business meeting with the royal, who denies the allegations through a London lawyer: “Our client is surprised and saddened by this allegation, which arrives eight months after the alleged incident and via a national newspaper. The account is denied.”

The CPS said last month that it had considered the evidence, but concluded that it could not prosecute Nahyan for sexual assault because the alleged attack had occurred outside its jurisdiction. If it is to prosecute under universal jurisdiction, the CPS requires evidence that the suspect is a public official, that they “intentionally inflicted severe pain or suffering” on another person and that they did so in “the performance or purported performance of their official duties”.

The CPS said that while it was satisfied Nahyan was a public official and that the alleged attack would have caused McNamara pain and suffering, it found there was not enough evidence to suggest Nahyan was acting in his official duties at the time.

“We took into account the complainant’s belief that she was attending a meeting about work when she agreed to meet with the suspect. However, her understanding of the nature of the meeting is not sufficient by itself to prove that the suspect was purporting to act in the performance of his official duties,” the CPS said. “From the evidence, the suspect’s conduct in arranging the meeting and during the meeting suggests the contrary, that he considered this to be a social meeting and did not want to discuss work.”

But McNamara said there was no reason for her to meet with Nahyan but work. “Of course I was lured there on the basis that it was a professional meeting. I simply wouldn’t have gone otherwise. I had never had one-on-one or social contact with this man before. He’s older than my dad. If a member of the royal family or the head of the organisation you work for asks to meet, with little explanation, it would be strange to assume that that person intended that meeting to be in any way informal,” she told the Guardian.

“I am not naive, I believe that anyone else in my position would have attended the meeting with the same understanding that I had. The royal family operate by their own rules in the UAE, and I was not working a nine-to-five job. I was on a posting abroad and I was often required to take meetings and calls at strange hours. He used his professional status to lure me there. Indeed, the festival was discussed in the initial stages of the meeting, before the assault. There’s so much that proves that I was there in a professional capacity.

“Even so, I just don’t understand why his understanding of the nature of the meeting would be more important than mine, or why either of our ideas about the nature of the meeting would make what he did to me acceptable.”

McNamara alleges that she was taken to a villa on a private island, where her phone was taken from her and Nahyan sexually assaulted her. She reported the allegation to embassy and festival staff, then to UK police in July.

“I am aware of the CPS’s disappointing recent record on prosecuting crimes against women, so, although I had been preparing myself for this outcome, I was surprised by aspects of their decision,” said McNamara, who first went public with her accusations in the Sunday Times in October.

She will be requesting a review under the CPS victim right to review scheme. “I knew the moment I left that villa that I wouldn’t get justice for what he did to me, because of who he is … but I just hope to get it in front of a judge, for them to tell me that decision, rather than the CPS,” she said.

Helena Kennedy, QC, who has been assisting McNamara, criticised the CPS for its decision. “Unfortunately, the CPS has an abysmal record on sexual offences and its failure to act and secure justice for women. It is like the Foreign Office: they take public positions about taking these crimes seriously and then do nothing when the opportunity arises,” said Kennedy. “We have told the CPS that we want a review of their decision and have asked for the opportunity to make representations to them.”

Kennedy said she had also raised the issue of Magnitsky targeted sanctions with the Foreign Office, which she said would mean a visa ban on the sheikh to prevent his entry into the UK and a freezing order on his assets here.

The CPS decision, said McNamara, sends “a clear message to this man and those committing similar crimes that as long as they’re of economic value to the UK, they can do whatever they want, at women’s or anyone’s expense and just get away with it”.

She said she would continue fighting her case: “Especially during lockdown and knowing what we do about the increase in domestic violence during these times, how can I, with a clear conscience, speak publicly to encourage other women to come forward and report instances with this man or anyone else, if I don’t keep going?”