diff --git a/src/palette.cpp b/src/palette.cpp
--- a/src/palette.cpp
+++ b/src/palette.cpp
@@ -23,8 +23,6 @@
 
 Palette _cur_palette;
 
-byte _colour_gradient[COLOUR_END][8];
-
 static std::recursive_mutex _palette_mutex; ///< To coordinate access to _cur_palette.
 
 /**
@@ -295,3 +293,38 @@ TextColour GetContrastColour(uint8_t bac
 	/* Compare with threshold brightness which defaults to 128 (50%) */
 	return sq1000_brightness < ((uint) threshold) * ((uint) threshold) * 1000 ? TC_WHITE : TC_BLACK;
 }
+
+/**
+ * Lookup table of colour shades for all 16 colour gradients.
+ * 8 colours per gradient from darkest (0) to lightest (7)
+ */
+struct ColourGradients
+{
+	using ColourGradient = std::array<byte, 8>;
+
+	static inline std::array<ColourGradient, COLOUR_END> gradient{};
+};
+
+/**
+ * Get colour gradient palette index.
+ * @param colour Colour.
+ * @param shade Shade level from 1 to 7.
+ * @returns palette index of colour.
+ */
+byte GetColourGradient(Colours colour, uint8_t shade)
+{
+	return ColourGradients::gradient[colour % COLOUR_END][shade % 8];
+}
+
+/**
+ * Set colour gradient palette index.
+ * @param colour Colour.
+ * @param shade Shade level from 1 to 7.
+ * @param palette_index Palette index to set.
+ */
+void SetColourGradient(Colours colour, uint8_t shade, byte palette_index)
+{
+	assert(colour < COLOUR_END);
+	assert(shade < 8);
+	ColourGradients::gradient[colour % COLOUR_END][shade % 8] = palette_index;
+}