PR Week this week includes a piece on why and how PR people need to adopt marketing skills. 

This is when you take a step back and think about it, an astonishing statement.  It suggests that PR people do now know what marketing is, what it does and the skill sets their marketing colleagues hold.

How can a successful comms function work in isolation from its marketing colleagues?  

I suspect, outside the PR agency bubble, this is not the case.  A PR/comms function will be an integrated part of marketing and business development space. That is certainly the case in the professional services sector. 

Perhaps the real issue is not that PR practitioners need to better understand and adopt a marketing skill set, but those working in PR agencies need a better understanding of the wider marketing function.