diff --git a/prog/kube-peers/annotations.go b/prog/kube-peers/annotations.go
index 86915618..20b45cdd 100644
--- a/prog/kube-peers/annotations.go
+++ b/prog/kube-peers/annotations.go
@@ -73,8 +73,10 @@ const (
 	retryPeriod  = time.Second * 2
 	jitterFactor = 1.0
 
+	// Prefix all our annotation keys with this string so they don't clash with anyone else's
+	KubePeersPrefix = "kube-peers.weave.works/"
 	// KubePeersAnnotationKey is the default annotation key
-	KubePeersAnnotationKey = "kube-peers.weave.works/peers"
+	KubePeersAnnotationKey = KubePeersPrefix + "peers"
 )
 
 func (cml *configMapAnnotations) Init() error {
@@ -130,13 +132,32 @@ func (cml *configMapAnnotations) UpdatePeerList(list peerList) error {
 	return cml.UpdateAnnotation(KubePeersAnnotationKey, string(recordBytes))
 }
 
+// Clean up a string so it meets the Kubernetes requiremements for Annotation keys:
+// name part must consist of alphanumeric characters, '-', '_' or '.', and must
+// start and end with an alphanumeric character (e.g. 'MyName', or 'my.name', or '123-abc')
+func cleanKey(key string) string {
+	buf := []byte(key)
+	for i, c := range buf {
+		if (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c == '-' || c == '_' || c == '.' || c == '/' {
+			continue
+		}
+		buf[i] = '_'
+	}
+	return string(buf)
+}
+
+func (cml *configMapAnnotations) GetAnnotation(key string) (string, bool) {
+	value, ok := cml.cm.Annotations[cleanKey(key)]
+	return value, ok
+}
+
 func (cml *configMapAnnotations) UpdateAnnotation(key, value string) (err error) {
 	if cml.cm == nil {
 		return errors.New("endpoint not initialized, call Init first")
 	}
 	// speculatively change the state, then replace with whatever comes back
 	// from Update(), which will be the latest on the server whatever happened
-	cml.cm.Annotations[key] = value
+	cml.cm.Annotations[cleanKey(key)] = value
 	cml.cm, err = cml.Client.ConfigMaps(cml.Namespace).Update(cml.cm)
 	return err
 }
@@ -147,7 +168,7 @@ func (cml *configMapAnnotations) RemoveAnnotation(key string) (err error) {
 	}
 	// speculatively change the state, then replace with whatever comes back
 	// from Update(), which will be the latest on the server whatever happened
-	delete(cml.cm.Annotations, key)
+	delete(cml.cm.Annotations, cleanKey(key))
 	cml.cm, err = cml.Client.ConfigMaps(cml.Namespace).Update(cml.cm)
 	return err
 }
@@ -160,7 +181,7 @@ func (cml *configMapAnnotations) RemoveAnnotationsWithValue(valueToRemove string
 	// from Update(), which will be the latest on the server whatever happened
 	for key, value := range cml.cm.Annotations {
 		if value == valueToRemove {
-			delete(cml.cm.Annotations, key)
+			delete(cml.cm.Annotations, key) // don't need to clean this key as it came from the map
 		}
 	}
 	cml.cm, err = cml.Client.ConfigMaps(cml.Namespace).Update(cml.cm)
diff --git a/prog/kube-peers/main.go b/prog/kube-peers/main.go
index 1961f70c..8872a4a6 100644
--- a/prog/kube-peers/main.go
+++ b/prog/kube-peers/main.go
@@ -122,7 +122,7 @@ func reclaimRemovedPeers(weave *weaveapi.Client, cml *configMapAnnotations, node
 			common.Log.Debugln("[kube-peers] Preparing to remove disappeared peer", peer)
 			okToRemove := false
 			// 3. Check if there is an existing annotation with key X
-			if existingAnnotation, found := cml.cm.Annotations[peer.PeerName]; found {
+			if existingAnnotation, found := cml.GetAnnotation(KubePeersPrefix + peer.PeerName); found {
 				common.Log.Debugln("[kube-peers] Existing annotation", existingAnnotation)
 				// 4.   If annotation already contains my identity, ok;
 				if existingAnnotation == myPeerName {
@@ -131,7 +131,7 @@ func reclaimRemovedPeers(weave *weaveapi.Client, cml *configMapAnnotations, node
 			} else {
 				// 5.   If non-existent, write an annotation with key X and contents "my identity"
 				common.Log.Debugln("[kube-peers] Noting I plan to remove ", peer.PeerName)
-				if err := cml.UpdateAnnotation(peer.PeerName, myPeerName); err == nil {
+				if err := cml.UpdateAnnotation(KubePeersPrefix+peer.PeerName, myPeerName); err == nil {
 					okToRemove = true
 				}
 			}
@@ -155,7 +155,7 @@ func reclaimRemovedPeers(weave *weaveapi.Client, cml *configMapAnnotations, node
 					}
 					common.Log.Infoln("[kube-peers] Removing annotation ", peer.PeerName)
 					// 7b.    Remove annotation with key X
-					return cml.RemoveAnnotation(peer.PeerName)
+					return cml.RemoveAnnotation(KubePeersPrefix + peer.PeerName)
 				})
 				common.Log.Debugln("[kube-peers] Finished removal of ", peer.PeerName)
 			}