Be careful of the UK system, however, if you do want a research degree. You can pass the masters without that much difficulty, but it's a different matter (esp. at LSE) doing well. And you need to do very well to be admitted to a research degree.
In the UK, no department worth getting a PhD from will admit a masters student who did not get at least a "merit" average. The clear majority of my masters cohort at LSE did not get this kind of grade, including some very bright people. To get into LSE's PhD you need to take the harder courses and get a distinction or close. So we're talking about the top 15 percent of your cohort.
There are people who did the various Econ masters at LSE who have been admitted to top 10 programmes in the US on the basis of their undergrad grades, and not made the grade for LSE. And in the UK, assessment is solely by a single exam in each subject at the end of the year, so a single bad day can knock you out. There'll be no mid-terms, no collaborative problem sets, etc to help smooth out your grades.
So in these terms, there is also an incredibly high "failure" rate in the UK in terms of people who come in aiming (ultimately) for a research degree but who do not make a good enough grade to actually do so.
However, if you don't want to go into academia, I think getting a PhD is a total waste frankly. In the US, because top places only offer PhDs and not terminal masters, a PhD has become a default for those who want serious economics training. In the UK, the Bachelors itself is fairly in-depth and the masters is a pretty serious degree. So the option of getting serious training while not spending (on average) 5-6 years getting it does exist.
Few of the US PhDs I know working in the private sector are using anything like the full range of skills they once had. The PhD is very inefficient (three or four years>=$250,000 of lost earnings), and there's a huge glut at the moment.
A PhD is time consuming and stressful, in the US or the UK. So unless you have a real interest in research don't go in for the PhD as a "decorative" degree.