diff --git a/app/broadcast_areas/__init__.py b/app/broadcast_areas/__init__.py
index 0631f37cd..5e2df3292 100644
--- a/app/broadcast_areas/__init__.py
+++ b/app/broadcast_areas/__init__.py
@@ -1,8 +1,8 @@
 from notifications_utils.formatters import formatted_list
+from notifications_utils.polygons import Polygons
 from notifications_utils.serialised_model import SerialisedModelCollection
 from werkzeug.utils import cached_property
 
-from .polygons import Polygons
 from .populations import CITY_OF_LONDON
 from .repo import BroadcastAreasRepository
 
diff --git a/app/broadcast_areas/create-broadcast-areas-db.py b/app/broadcast_areas/create-broadcast-areas-db.py
index e3eb5f6ec..34956be66 100755
--- a/app/broadcast_areas/create-broadcast-areas-db.py
+++ b/app/broadcast_areas/create-broadcast-areas-db.py
@@ -6,8 +6,8 @@ from pathlib import Path
 
 import geojson
 from notifications_utils.formatters import formatted_list
+from notifications_utils.polygons import Polygons
 
-from polygons import Polygons
 from populations import (
     BRYHER,
     CITY_OF_LONDON,
diff --git a/app/broadcast_areas/polygons.py b/app/broadcast_areas/polygons.py
deleted file mode 100644
index 602eb2297..000000000
--- a/app/broadcast_areas/polygons.py
+++ /dev/null
@@ -1,186 +0,0 @@
-import itertools
-
-from shapely.geometry import (
-    JOIN_STYLE,
-    GeometryCollection,
-    MultiPolygon,
-    Polygon,
-)
-from shapely.ops import unary_union
-from werkzeug.utils import cached_property
-
-
-class Polygons():
-
-    approx_metres_to_degree = 111_320
-    approx_square_metres_to_square_degree = approx_metres_to_degree ** 2
-    square_degrees_to_square_miles = (
-        approx_square_metres_to_square_degree / (1000 * 1000) * 0.386102
-    )
-
-    # Estimated amount of bleed into neigbouring areas based on typical
-    # range/separation of cell towers.
-    approx_bleed_in_degrees = 1_500 / approx_metres_to_degree
-
-    # Controls how much buffer to add for a shape of a given perimeter.
-    # Smaller number means more buffering and a smoother shape. For
-    # example `1000` means 1m of buffer for every 1km of perimeter, or
-    # 20m of buffer for a 5km square. This gives us control over how
-    # much we fill in very concave features like channels, harbours and
-    # zawns.
-    perimeter_to_buffer_ratio = 360
-
-    # Ratio of how much detail a shape of a given perimeter has once
-    # simplified. Smaller number means less detail. For example `1000`
-    # means that for a shape with a perimeter of 1000m, the simplified
-    # line will never deviate more than 1m from the original.
-    # Or for a 5km square, the line won’t deviate more than 20m. This
-    # gives us approximate control over the total number of points.
-    perimeter_to_simplification_ratio = 1_620
-
-    # The threshold for removing very small areas from the map. These
-    # areas are likely glitches in  the data where the shoreline hasn’t
-    # been subtracted from the land properly
-    minimum_area_size_square_metres = 6_500
-
-    def __init__(self, polygons):
-        if not polygons:
-            self.polygons = []
-        elif isinstance(polygons[0], list):
-            self.polygons = [
-                Polygon(polygon) for polygon in polygons
-            ]
-        else:
-            self.polygons = polygons
-
-    def __getitem__(self, index):
-        return self.polygons[index]
-
-    def __len__(self):
-        return len(self.polygons)
-
-    @cached_property
-    def perimeter_length(self):
-        return sum(
-            polygon.length for polygon in self
-        )
-
-    @cached_property
-    def buffer_outward_in_degrees(self):
-        return (
-            # If two areas are close enough that the distance between
-            # them is less than the minimum bleed of a cell
-            # broadcast then this joins them together. The aim is to
-            # reduce the total number of polygons in areas with many
-            # small shapes like Orkney or the Isles of Scilly.
-            self.approx_bleed_in_degrees / 3
-        ) + (
-            self.perimeter_length / self.perimeter_to_buffer_ratio
-        )
-
-    @cached_property
-    def buffer_inward_in_degrees(self):
-        return self.buffer_outward_in_degrees - (
-            # We should leave the shape expanded by at least the
-            # simplification tolerance in all places, so the
-            # simplification never moves a point inside the original
-            # shape. In practice half of the tolerance is enough to
-            # acheive this.
-            self.simplification_tolerance_in_degrees / 2
-        )
-
-    @cached_property
-    def simplification_tolerance_in_degrees(self):
-        return self.perimeter_length / self.perimeter_to_simplification_ratio
-
-    @cached_property
-    def smooth(self):
-        buffered = [
-            polygon.buffer(
-                self.buffer_outward_in_degrees,
-                resolution=4,
-                join_style=JOIN_STYLE.round,
-            )
-            for polygon in self
-        ]
-        unioned = union_polygons(buffered)
-        debuffered = [
-            polygon.buffer(
-                -1 * self.buffer_inward_in_degrees,
-                resolution=1,
-                join_style=JOIN_STYLE.bevel,
-            )
-            for polygon in unioned
-        ]
-        flattened = list(itertools.chain(*[
-            flatten_polygons(polygon) for polygon in debuffered
-        ]))
-        return Polygons(flattened)
-
-    @cached_property
-    def simplify(self):
-        return Polygons([
-            polygon.simplify(self.simplification_tolerance_in_degrees)
-            for polygon in self
-        ])
-
-    @cached_property
-    def bleed(self):
-        return Polygons(union_polygons([
-            polygon.buffer(
-                self.approx_bleed_in_degrees,
-                resolution=4,
-                join_style=JOIN_STYLE.round,
-            )
-            for polygon in self
-        ]))
-
-    @cached_property
-    def remove_too_small(self):
-        return Polygons([
-            polygon for polygon in self
-            if (
-                polygon.area * self.approx_square_metres_to_square_degree
-            ) > (
-                self.minimum_area_size_square_metres
-            )
-        ])
-
-    @cached_property
-    def as_coordinate_pairs_long_lat(self):
-        return [
-            [[x, y] for x, y in polygon.exterior.coords]
-            for polygon in self
-        ]
-
-    @cached_property
-    def as_coordinate_pairs_lat_long(self):
-        return [
-            [[y, x] for x, y in coordinate_pairs]
-            for coordinate_pairs in self.as_coordinate_pairs_long_lat
-        ]
-
-    @cached_property
-    def point_count(self):
-        return len(list(itertools.chain(*self.as_coordinate_pairs_long_lat)))
-
-    @property
-    def estimated_area(self):
-        return sum(
-            polygon.area for polygon in self
-        ) * self.square_degrees_to_square_miles
-
-
-def flatten_polygons(polygons):
-    if isinstance(polygons, GeometryCollection):
-        return []
-    if isinstance(polygons, MultiPolygon):
-        return [
-            p for p in polygons
-        ]
-    else:
-        return [polygons]
-
-
-def union_polygons(polygons):
-    return flatten_polygons(unary_union(polygons))
diff --git a/app/models/broadcast_message.py b/app/models/broadcast_message.py
index 8c6776e67..a6a0185f0 100644
--- a/app/models/broadcast_message.py
+++ b/app/models/broadcast_message.py
@@ -1,12 +1,12 @@
 import itertools
 from datetime import datetime, timedelta
 
+from notifications_utils.polygons import Polygons
 from notifications_utils.template import BroadcastPreviewTemplate
 from orderedset import OrderedSet
 from werkzeug.utils import cached_property
 
 from app.broadcast_areas import CustomBroadcastAreas, broadcast_area_libraries
-from app.broadcast_areas.polygons import Polygons
 from app.formatters import round_to_significant_figures
 from app.models import JSONModel, ModelList
 from app.models.user import User