There's also the Highly Skilled Migrant Programme, where someone from overseas can obtain the right to move to the UK and look for a job while they're over here if they can earn sufficiently many points through a combination of educational qualifications, work experience, past earnings, exceptional achievement in their field, being a General Practitioner of Medicine and/or their partners' achievements. Additionally, the usual common-sense safeguards apply: stick here, work here and don't draw benefits. The bar is set at quite a height, though substantial concessions are made to those aged under 28. We sometimes heard of parties' plans to establish "an Australian-style point scheme" for potential economic migrants; I am annoyed that Labour didn't defend the practices they implemented themselves by saying "Oi, mush, we've got one already".
I Am Not A Lawyer, but I am a gamer, and I realised something interesting today. The point allocations make it substantially easier for someone to get to 55 or 60 points under the scheme than to get to 65. Someone aged 28+ would probably get to 60 points through 25 for a Masters degree and 35 points for 5 years' graduate-level work experience including 2 years at a senior level (roughly "a dozen graduates underneath them"). Various other combinations exist, but the system is set up to award points in 25s and 35s. (For someone under 28, it's even easier - 5 points age bonus, 25 for a Masters degree and 25 for 2 years' graduate level work experience takes you to 55.)
In comparison to those, the last 10 points are easy; have a spouse with a bachelors' degree, or two years of graduate-level experience. Heck, you don't need to be married - two years of unmarried but established partnership will suffice, in whatever gender combination. This spouse needs only the first degree or the experience and nothing else to earn you both the points.
It surprises me that we don't hear more about people marrying each other, or forming such partnerships, purely so that one of them can gain those last 10 points and the other can piggy-back their way into Britain as a dependent of the first. (Presumably these partnerships could be dissolved at a later date when both parties would qualify for indefinite leave to remain individually.) Oh, I'm sure it happens, but I also suspect it doesn't happen frequently enough to attract attention.
My own view is that if we must have a brain drain around the world, which is not ideal, then "we" ought to be selfish and make it easy for "ourselves" to be a net beneficiary from the phenomenon. Accordingly, I would increase the score earnt for having a PhD from 30 points to 40, so any PhD with five years' graduate level work experience would qualify, regardless of partnership status and make a distinction between good and excellent Masters degrees, so that anyone under 28 with an excellent Masters degree and two years' graduate level work would qualify even if alone. Effectively, that's not going to allow more of these highly desirable in on its own, just that it's going to permit them to qualify on their own, rather than having to form a sham partnership with a graduate in order to make the grade.