diff --git a/Shower/Couplings/ShowerAlphaQED.cc b/Shower/Couplings/ShowerAlphaQED.cc
--- a/Shower/Couplings/ShowerAlphaQED.cc
+++ b/Shower/Couplings/ShowerAlphaQED.cc
@@ -1,56 +1,63 @@
 // -*- C++ -*-
 //
 // ShowerAlphaQED.cc is a part of Herwig - A multi-purpose Monte Carlo event generator
 // Copyright (C) 2002-2007 The Herwig Collaboration
 //
 // Herwig is licenced under version 2 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 //
 // This is the implementation of the non-inlined, non-templated member
 // functions of the ShowerAlphaQED class.
 //
 
 #include "ShowerAlphaQED.h"
 #include "ThePEG/StandardModel/StandardModelBase.h"
 #include "ThePEG/Repository/EventGenerator.h"
+#include "ThePEG/Interface/Parameter.h"
 #include "ThePEG/Interface/ClassDocumentation.h"
 #include "ThePEG/Persistency/PersistentOStream.h"
 #include "ThePEG/Persistency/PersistentIStream.h"
 
 using namespace Herwig;
 
 void ShowerAlphaQED::persistentOutput(PersistentOStream & os) const {
   os << _alpha;
 }
 
 void ShowerAlphaQED::persistentInput(PersistentIStream & is, int) {
   is >> _alpha;
 }
 
 ClassDescription<ShowerAlphaQED> ShowerAlphaQED::initShowerAlphaQED;
 // Definition of the static class description member.
 
 void ShowerAlphaQED::Init() {
 
   static ClassDocumentation<ShowerAlphaQED> documentation
     ("This (concrete) class describes the QED alpha running.");
 
+  static Parameter<ShowerAlphaQED,double> interfaceAlpha
+    ("Alpha",
+     "The value of alpha_EM",
+     &ShowerAlphaQED::_alpha, 1./137., 0., 1.,
+     false, false, Interface::limited);
+
 }
 
 double ShowerAlphaQED::value(const Energy2) const {
   return scaleFactor()*_alpha;
 }
 
 double ShowerAlphaQED::overestimateValue() const {
   return scaleFactor()*_alpha;
 }
 
 double ShowerAlphaQED::ratio(const Energy2) const {
   return 1.;
 }
 
 void ShowerAlphaQED::doinit() throw(InitException) {
   ShowerAlpha::doinit();
   _alpha=generator()->standardModel()->alphaEM();
 }