diff --git a/README.md b/README.md
index e497dca..bacfe90 100644
--- a/README.md
+++ b/README.md
@@ -2,12 +2,14 @@
 Styles for Mapbox vector tiles (MVT) usable with
 [QtPBFImagePlugin](https://github.com/tumic0/QtPBFImagePlugin).
 
-There are (at least) three incompatible MVT schemas out there:
+There are (at least) four incompatible MVT schemas out there:
 - Mapbox
 - OpenMapTiles (eg. MapTiler, Mapilion)
 - Tilezen (eg. HERE, Nextzen)
+- Ordnance Survey
 
 This repository contains Mapbox GL styles usable with QtPBFImagePlugin for
 each schema. The styles are usualy copies (sometimes with minor tweaks) of
 the original styles created by Mapbox, Openmaptiles or Apollo Mapping before
-they have moved to the new style format (expressions).
+they have moved to the new style format (expressions). The OrdnanceSurvey
+style is a backport of the official OS style.