I won't rehearse the issues around this one as have 
blogged previously about it. Just to say I think the IIC's update on its audit paper is a step forward. The position adopted by a previous IIC paper did not reflect all investor opinion - which is split on the issue of mandatory rotation -  though the updated version issued in Dec 2012 does acknowledge differing views.
The problem, as I've mentioned before, is that some in the auditing business rather naughtily used the Dec 2012 IIC paper to suggest that the body - and investors generally - were opposed to mandatory rotation. 
eg - 
the UK’s Institutional Investor
Committee – made up of representatives of from the Association of British
Insurers, the Investment Management Association and the National Association of
Pension Funds, which together manage or own £4 trillion of assets – set out in
a paper in December 2012 clear opposition to mandatory rotation. 
Therefore it is helpful that the IIC makes clear that it 
"has not reached a 
consensus on the merits of mandatory auditor rotation."
Full blurb below
 
Update on IIC Audit Position Paper
UK institutional investors continue to believe that ensuring a high 
quality of audits is vital in ensuring that markets value and trust the 
information reported. As set out in the December 2012 paper, investors 
support the objectives of the European Commission's proposals to 
safeguard auditor independence and objectivity and to improve the 
communications between auditors, audit committees and shareholders.
Investors are concerned that, where auditors hold office for long 
periods, this can affect their independence and objectivity, which are 
vital in ensuring audit quality. However, the IIC has not reached a 
consensus on the merits of mandatory auditor rotation.
The December 2012 IIC Position Paper remains reflective of UK institutional investor views on the remainder of the EU proposals.
From 
here