I went through a two-stage interview process, one was technical and one was behavioural. Both interviews were pleasant, the interviewers were very friendly, and we had some in-depth technical discussions on how the company is building their software and AI products. Soon after I finished the second interview, I received a call from a member of their recruitment team, he said he would like to make me an offer, however, he needs to first make sure that I can pass the security clearance. He asked me a bunch of questions (e.g. have you left the UK for more than 2 months in the past 5 years), in the end, he said he had to ask someone higher up about this issue, and he would send me an email as soon as he has an answer. Two weeks later, I didn't hear anything back. So I sent their recruitment team an email, inquiring about my application. A day later, I received a generic email telling me that my application has been rejected with no explanation whatsoever. The thing is, even though I wasn't born in the UK, I came to the UK when I was a child and I hold a British passport longer than I held my previous passport, and I'm British only, i.e. I don't have dual citizenship. So I thought the security clearance isn't going to be an issue, but apparently, that is not the case. Someone must've looked into my background and decided it was not possible for me to obtain a security clearance, for whatever reason. But more importantly, they should at least have the common courtesy of getting back to me and explaining the situation, especially since the person from their recruitment team said he would do so. Instead, even when I sent them an email after two weeks of no contract, all they sent me was a generic rejection email. I guess the key takeaway is that, unless you are British your whole life, you shouldn't apply to this company, because it's likely going to be a waste of your time. The lack of professionalism in their recruitment team is concerning to say the least.