Alan will step down at the end of the year after a total of almost 36 years with the Trades Union Congress.
He has been Regional Secretary of the TUC in the North West since 1985.
He said: 'It has been a great privilege to have been able to serve the TUC and to have worked with so many good colleagues'.
'My focus and commitment will be undiminished in the remaining period of my employment as we enter a critical period for our movement in the battle against austerity'.
Tributes have already started pouring in from trade union members all over the North West.
Mr Manning's successor is likely to be appointed before the end of the year, with the post of Regional Secretary being advertised from next week.
Briefing document (200 words) issued 25 Sep 2012
This page http://www.tuc.org.uk/the_tuc/tuc-21450-f0.cfm
printed 24 May 2013 at 04:57 hrs by 126.96.36.199