Explain what is meant by the concept of the minimum efficient scale (MES) and consider how JD Wetherspoon public house chain has affected the MES within their industry.

Here are the basics about MES:
Minimum efficient scale - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Minimum_efficient_scale)

As for JD Wetherspoon, we cannot answer that as we don't know the details.

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