Neath's Constituency Labour Party has paid tribute to Mr Hain's service.
In a statement it said:
"For the last 23 years Peter Hain has served the people of Neath tirelessly, fighting for constituents and our Labour Party values.
Holding government positions like secretary of state for Wales he delivered further devolution for the people of Wales and at the department of trade and Industry he brought many hundreds of millions of pounds of compensation to thousands of chronically ill miners.
His unstinting work to negotiate a peace settlement in Northern Ireland has brought a stability to the area that just years before no-one would have thought possible.
In the Neath constituency he has helped many thousands of people through his surgeries and advice office. For over two decades he has been a popular campaigning MP fighting for residents and taking up the causes with great passion and commitment, and putting Neath on the map.
We thank Peter unreservedly for what he has done for us and are sure he will continue to play an active role in the constituency and the party.
As a constituency party we now look to begin the process of finding our parliamentary candidate for the 2015 general election and winning a Labour majority.
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