diff --git a/Generators/Rivet_i/src/Rivet_i.cxx b/Generators/Rivet_i/src/Rivet_i.cxx
index 14c36982f5ddd2d078f1a56bce39c08f9e0687b8..0dc0f53dab5c3250f46e2bddb587bd4e97d57b78 100644
--- a/Generators/Rivet_i/src/Rivet_i.cxx
+++ b/Generators/Rivet_i/src/Rivet_i.cxx
@@ -409,7 +409,7 @@ const HepMC::GenEvent* Rivet_i::checkEvent(const HepMC::GenEvent* event) {
 
 
   if (!modEvent->valid_beam_particles()) {
-    if (m_isSPG && modEvent->particles_size() == 1) {
+    if (m_isSPG) {
       // a single particle gun only has one particle without
       // a production vertex. In this kludge, we add a 
       // dummy vertex with an exact copy of the particle