diff --git a/etl/convert_opentoid_bng_latlon.py b/etl/convert_opentoid_bng_latlon.py
new file mode 100644
index 00000000..ccf874c3
--- /dev/null
+++ b/etl/convert_opentoid_bng_latlon.py
@@ -0,0 +1,30 @@
+"""Convert BNG values in OpenTOID data to latitude/longitude"""
+import csv
+import glob
+import os
+import sys
+from convertbng.util import convert_lonlat
+from pandas import read_csv
+
+
+csv.field_size_limit(sys.maxsize)
+
+
+def main(opentoid_path):
+    ot_paths = sorted(glob.glob(os.path.join(opentoid_path, "*.csv")))
+    for ot_path in ot_paths:
+        convert_opentoid_coordinates(ot_path)
+
+
+def convert_opentoid_coordinates(ot_path):
+    """Overwrite the input csv, adding the longitute/latitude from eastings/northings"""
+    ot_data = read_csv(ot_path)
+    ot_data['longitude'], ot_data['latitude'] = convert_lonlat(ot_data['EASTING'], ot_data['NORTHING'])
+    ot_data.to_csv(ot_path)
+
+
+if __name__ == '__main__':
+    if len(sys.argv) != 2:
+        print("Usage: convert_opentoid_bng_latlon.py ./path/to/opentoid/dir")
+        exit(-1)
+    main(sys.argv[1])
diff --git a/etl/requirements.txt b/etl/requirements.txt
index 55188359..2623c138 100644
--- a/etl/requirements.txt
+++ b/etl/requirements.txt
@@ -5,3 +5,4 @@ psycopg2==2.7.5
 shapely==1.7
 retrying==1.3.3
 requests==2.23.0
+convertbng==0.6.37