diff --git a/build/check.xsl b/build/check.xsl
index 6765ac21..4bfcb7b8 100644
--- a/build/check.xsl
+++ b/build/check.xsl
@@ -16,6 +16,7 @@
 	xmlns:set="http://exslt.org/sets"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xmlns:idpdisc="urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol"
+	xmlns:ukfxMail="xalan://uk.org.ukfederation.xalan.Mail"
 	xmlns:ukfxm="xalan://uk.org.ukfederation.xalan.Members"
 	xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
 
@@ -196,6 +197,15 @@
 	</xsl:template>
 	
 	
+	<!--
+		Check for badly formatted e-mail addresses.
+	-->
+	<xsl:template match="md:EmailAddress[ukfxMail:dodgyAddress(.)]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">badly formatted e-mail address: '<xsl:value-of select='.'/>'</xsl:with-param>
+		</xsl:call-template>
+	</xsl:template>
+	
 	<!--
 		Common template to call to report a fatal error on some element within an entity.
 	-->