diff --git a/core/palette-templates/TwentyTwenties.tid b/core/palette-templates/TwentyTwenties.tid
index 1bc7735c3..18558b4ff 100644
--- a/core/palette-templates/TwentyTwenties.tid
+++ b/core/palette-templates/TwentyTwenties.tid
@@ -18,7 +18,9 @@ base-secondary: rgb(236, 212, 58)
 base-tertiary: rgb(135, 239, 70)
 
 # Contrast tests
-?background-foreground-contrast: [function[colour],[background]] [function[colour],[base-background]] +[colour-contrast:DeltaPhi[]compare:number:gt[25]then[ok]else[Foreground/background contrast is too low]]
+?background-foreground-contrast: [tf.check-colour-contrast[background],[foreground],[125]]
+?alert-contrast: [tf.check-colour-contrast[alert-background],[foreground],[25]]
+?code-contrast: [tf.check-colour-contrast[code-background],[code-foreground],[25]]
 
 # Colour definitions
 alert-background: [function[colour],[base-secondary]colour-oklch:l[0.9]]
diff --git a/core/wiki/macros/CSS.tid b/core/wiki/macros/CSS.tid
index f367d11f8..59826452d 100644
--- a/core/wiki/macros/CSS.tid
+++ b/core/wiki/macros/CSS.tid
@@ -2,6 +2,8 @@ title: $:/core/macros/CSS
 tags: $:/tags/Macro
 
 \procedure actions-compile-palette-filtered(tempPalette,outputTitle)
+<!-- Note the join, needed to cope with palette entries containing spaces -->
+\function colour(name) [<tv-palette-name>getindex<name>] :else[<tv-palette-name>get[palette-import]getindex<name>] :map[subfilter<currentTiddler>join[ ]]
 <!-- Make the colour function use the input palette -->
 <$let
 	tv-palette-name=<<tempPalette>>
@@ -77,6 +79,10 @@ tags: $:/tags/Macro
 [function[colour],<name>]
 \end color
 
+\function tf.check-colour-contrast(paletteEntryA,paletteEntryB,threshold)
+[function[colour],<paletteEntryA>] [function[colour],<paletteEntryB>] +[colour-contrast:DeltaPhi[]compare:number:gt<threshold>then[ok]] :else[<paletteEntryA>addsuffix[/]addsuffix<paletteEntryB>addsuffix[ contrast is too low]]
+\end tf.check-colour-contrast
+
 \define box-shadow(shadow)
 ``
 -webkit-box-shadow: $shadow$;
diff --git a/core/wiki/paletteswitcher.tid b/core/wiki/paletteswitcher.tid
index bdde81e4b..ced304b7b 100644
--- a/core/wiki/paletteswitcher.tid
+++ b/core/wiki/paletteswitcher.tid
@@ -24,3 +24,5 @@ title: $:/snippets/paletteswitcher
 		</$list>
 	</div>
 </$linkcatcher>
+
+{{$:/snippets/palettetests}}
diff --git a/core/wiki/palettetests.tid b/core/wiki/palettetests.tid
new file mode 100644
index 000000000..b7bd24d69
--- /dev/null
+++ b/core/wiki/palettetests.tid
@@ -0,0 +1,19 @@
+title: $:/snippets/palettetests
+
+<$let failureCount={{{ [[$:/temp/palette-colours]indexes[]prefix[?]] :filter[[$:/temp/palette-colours]getindex<currentTiddler>!match[ok]] +[count[]] }}}>
+
+<%if [<failureCount>compare:number:gt[0]] %>
+
+Palette test failures: <$text text=<<failureCount>>/>
+
+<$list filter="[[$:/temp/palette-colours]indexes[]prefix[?]sort[]]" variable="name">
+	<%if [[$:/temp/palette-colours]getindex<name>!match[ok]] %>
+		<div>
+			''<$text text={{{ [<name>removeprefix[?]] }}}/>'': <$text text={{{ [[$:/temp/palette-colours]getindex<name>] }}}/>
+		</div>
+	<%endif%>
+</$list>
+
+<%endif%>
+
+</$let>
diff --git a/editions/prerelease/tiddlers/palette.tid b/editions/prerelease/tiddlers/palette.tid
index afd78912b..9cd6f441c 100644
--- a/editions/prerelease/tiddlers/palette.tid
+++ b/editions/prerelease/tiddlers/palette.tid
@@ -1,3 +1,3 @@
 title: $:/palette
 
-$:/palettes/Vanilla
\ No newline at end of file
+$:/palettes/TwentyTwenties
\ No newline at end of file