diff --git a/build.xml b/build.xml
index e3a57880..70ea2d50 100644
--- a/build.xml
+++ b/build.xml
@@ -855,6 +855,7 @@
                 <arg value="${build.dir}/check_adfs.xsl"/>
                 <arg value="${build.dir}/check_idpdisc.xsl"/>
 				<arg value="${build.dir}/check_mdiop.xsl"/>
+				<arg value="${build.dir}/check_mdui.xsl"/>
                 <arg value="${build.dir}/check_misc.xsl"/>
 				<arg value="${build.dir}/check_namespaces.xsl"/>
                 <arg value="${build.dir}/check_shibboleth.xsl"/>
diff --git a/build/check_mdui.xsl b/build/check_mdui.xsl
new file mode 100644
index 00000000..3890576a
--- /dev/null
+++ b/build/check_mdui.xsl
@@ -0,0 +1,199 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+	check_mdui.xsl
+	
+	Checking ruleset containing rules associated with the SAML V2.0 Metadata
+	Extensions for Login and Discovery User Interface Version 1.0, see:
+
+		http://wiki.oasis-open.org/security/SAML2MetadataUI
+		
+	This ruleset reflects WD04, 4-Nov-2010.
+	
+	Some of these rules are simply checks on schema validity; those can
+	probably be removed and replaced by direct checks against the schema.
+	They are marked with comments to that effect.
+
+	Author: Ian A. Young <ian@iay.org.uk>
+
+-->
+<xsl:stylesheet version="1.0"
+	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+	xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
+	xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
+	xmlns:mdui="urn:oasis:names:tc:SAML:metadata:ui"
+	xmlns:set="http://exslt.org/sets"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
+
+	<!--
+		Common support functions.
+	-->
+	<xsl:import href="check_framework.xsl"/>
+	
+	<!--
+		Section 2.1
+		
+		<mdui:UIInfo> MUST NOT appear more than once within a given <md:Extensions> element.
+	-->
+	<xsl:template match="md:Extensions/mdui:UIInfo[position()>1]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">more than one UIInfo element in one Extensions element</xsl:with-param>
+		</xsl:call-template>		
+	</xsl:template>
+
+	<!--
+		Section 2.1
+		
+		The <mdui:UIInfo> container element [...] MUST appear within the
+		<md:Extensions> element of a role element (one whose type is based on
+		md:RoleDescriptorType).
+		
+		[The rule here further restricts the location to within either IDPSSODescriptor or
+		SPSSODescriptor elements, which are the ones we'll actually make use of.]
+	-->
+	<xsl:template match="mdui:UIInfo[not(parent::md:Extensions)]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">UIInfo appearing outside Extensions element</xsl:with-param>
+		</xsl:call-template>        
+	</xsl:template>
+	<xsl:template match="md:Extensions[mdui:UIInfo]
+		[not(parent::md:IDPSSODescriptor)][not(parent::md:SPSSODescriptor)]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">UIInfo appearing outside role descriptor element</xsl:with-param>
+		</xsl:call-template>        
+	</xsl:template>
+
+	<!--
+		Constraints across multiple elements within the container.
+		
+		DisplayName, Description, InformationURL and PrivacyStatementURL elements
+		are all required to have unique xml:lang values within their element type.
+	-->
+	<xsl:template match="mdui:UIInfo">
+		<!-- unique xml:lang over DisplayName elements -->
+		<xsl:call-template name="uniqueLang">
+			<xsl:with-param name="e" select="mdui:DisplayName"/>
+		</xsl:call-template>
+		
+		<!-- unique xml:lang over Description elements -->
+		<xsl:call-template name="uniqueLang">
+			<xsl:with-param name="e" select="mdui:Description"/>
+		</xsl:call-template>
+		
+		<!-- unique xml:lang over InformationURL elements -->
+		<xsl:call-template name="uniqueLang">
+			<xsl:with-param name="e" select="mdui:InformationURL"/>
+		</xsl:call-template>
+		
+		<!-- unique xml:lang over PrivacyStatementURL elements -->
+		<xsl:call-template name="uniqueLang">
+			<xsl:with-param name="e" select="mdui:PrivacyStatementURL"/>
+		</xsl:call-template>
+		
+		<!-- handle individual elements -->
+		<xsl:apply-templates select="*"/>
+	</xsl:template>
+	<xsl:template name="uniqueLang">
+		<xsl:param name="e"/>
+		<xsl:variable name="l" select="$e/@xml:lang"></xsl:variable>
+		<xsl:variable name="u" select="set:distinct($l)"/>
+		<xsl:if test="count($l) != count($u)">
+			<xsl:call-template name="fatal">
+				<xsl:with-param name="m">
+					<xsl:text>non-unique lang values on </xsl:text>
+					<xsl:value-of select="name($e)"/>
+					<xsl:text> elements</xsl:text>
+				</xsl:with-param>
+			</xsl:call-template>
+		</xsl:if>
+	</xsl:template>
+	
+	
+	<!--
+		Section 2.1.2 Element <mdui:DisplayName>
+	-->
+	<xsl:template match="mdui:DisplayName">
+		<xsl:call-template name="localisedNameType"/>
+	</xsl:template>
+
+	<!--
+		Section 2.1.3 Element <mdui:Description>
+	-->
+	<xsl:template match="mdui:Description">
+		<xsl:call-template name="localisedNameType"/>
+	</xsl:template>
+	
+	<!--
+		Section 2.1.4 Element <mdui:Logo>
+	-->
+	<xsl:template match="mdui:Logo">
+		<!-- Schema validity: must have a height attribute -->
+		<xsl:if test="not(@height)">
+			<xsl:call-template name="fatal">
+				<xsl:with-param name="m">missing @height on <xsl:value-of select="name()"/></xsl:with-param>
+			</xsl:call-template>
+		</xsl:if>
+		<!-- Schema validity: must have a width attribute -->
+		<xsl:if test="not(@width)">
+			<xsl:call-template name="fatal">
+				<xsl:with-param name="m">missing @width on <xsl:value-of select="name()"/></xsl:with-param>
+			</xsl:call-template>
+		</xsl:if>   
+	</xsl:template>
+	
+	<!--
+		Section 2.1.5 Element <mdui:InformationURL>
+	-->
+	<xsl:template match="mdui:InformationURL">
+		<xsl:call-template name="localisedNameType"/>
+	</xsl:template>
+	
+	<!--
+		Section 2.1.6 Element <mdui:PrivacyStatementURL>
+	-->
+	<xsl:template match="mdui:PrivacyStatementURL">
+		<xsl:call-template name="localisedNameType"/>
+	</xsl:template>
+	
+	<!--
+		Common ruleset for elements derived from localisedNameType.
+	-->
+	<xsl:template name="localisedNameType">
+		<!-- Schema validity: must have an xml:lang attribute -->
+		<xsl:if test="not(@xml:lang)">
+			<xsl:call-template name="fatal">
+				<xsl:with-param name="m">missing @xml:lang on <xsl:value-of select="name()"/></xsl:with-param>
+			</xsl:call-template>
+		</xsl:if>	
+	</xsl:template>
+	
+	<!--
+		Section 2.2
+		
+		The <mdui:DiscoHints> container element [...] MUST appear within the
+		<md:Extensions> element of an <md:IDPSSODescriptor> element.
+	-->
+	<xsl:template match="mdui:DiscoHints[not(parent::md:Extensions)]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">DiscoHints appearing outside Extensions element</xsl:with-param>
+		</xsl:call-template>        
+	</xsl:template>
+	<xsl:template match="md:Extensions[mdui:DiscoHints][not(parent::md:IDPSSODescriptor)]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">DiscoHints appearing outside IDPSSODescriptor element</xsl:with-param>
+		</xsl:call-template>        
+	</xsl:template>
+	
+	<!--
+		Section 2.2
+		
+		<mdui:DiscoHints> MUST NOT appear more than once within a given <md:Extensions> element.
+	-->
+	<xsl:template match="md:Extensions/mdui:DiscoHints[position()>1]">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">more than one DiscoHints element in one Extensions element</xsl:with-param>
+		</xsl:call-template>        
+	</xsl:template>
+	
+</xsl:stylesheet>