diff --git a/modules/purchase_trade/stock.py b/modules/purchase_trade/stock.py
index 287b3e4..bead915 100755
--- a/modules/purchase_trade/stock.py
+++ b/modules/purchase_trade/stock.py
@@ -1,6 +1,6 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-from trytond.model import fields
+from trytond.model import fields, Workflow
 from trytond.pool import Pool, PoolMeta
 from trytond.pyson import Bool, Eval, Id
 from trytond.model import (ModelSQL, ModelView)
@@ -470,13 +470,65 @@ class ShipmentIn(metaclass=PoolMeta):
     agent = fields.Many2One('party.party',"Booking Agent")
     service_order_key = fields.Integer("Service Order Key")
 
-    @classmethod
-    def __setup__(cls):
-        super().__setup__()
-        cls._buttons.update({
-            'compute': {},
-            'send': {},
-        })
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls._transitions |= set((
+            ('started', 'cancelled'),
+            ))
+        cls._buttons.update({
+            'compute': {},
+            'send': {},
+        })
+
+    @classmethod
+    def _stock_move_origin(cls, move):
+        return 'stock.move,%s' % move.id
+
+    @classmethod
+    def _delete_draft_account_moves_for_stock_moves(cls, moves):
+        moves = [move for move in moves if getattr(move, 'id', None)]
+        if not moves:
+            return
+
+        AccountMove = Pool().get('account.move')
+        account_moves = AccountMove.search([
+            ('origin', 'in', [cls._stock_move_origin(move) for move in moves]),
+            ])
+        posted = [
+            move for move in account_moves
+            if getattr(move, 'state', None) == 'posted']
+        if posted:
+            names = ', '.join(move.rec_name for move in posted[:5])
+            if len(posted) > 5:
+                names += '...'
+            raise UserError(
+                "Cannot cancel started shipment because stock accounting "
+                "move(s) are already posted: %s" % names)
+
+        draft_moves = [
+            move for move in account_moves
+            if getattr(move, 'state', None) != 'posted']
+        if draft_moves:
+            AccountMove.delete(draft_moves)
+
+    @classmethod
+    @ModelView.button
+    @Workflow.transition('cancelled')
+    def cancel(cls, shipments):
+        moves = [
+            move for shipment in shipments
+            for move in shipment.incoming_moves + shipment.inventory_moves]
+        cls._delete_draft_account_moves_for_stock_moves(moves)
+        super().cancel(shipments)
+        started_shipments = [
+            shipment for shipment in shipments
+            if shipment.state == 'started']
+        if started_shipments:
+            cls.write(started_shipments, {
+                'start_date': None,
+                'started_by': None,
+                })
 
     def get_vessel_type(self,name=None):
         if self.vessel:
diff --git a/modules/purchase_trade/tests/test_module.py b/modules/purchase_trade/tests/test_module.py
index 2e57ab9..ebbc9f5 100644
--- a/modules/purchase_trade/tests/test_module.py
+++ b/modules/purchase_trade/tests/test_module.py
@@ -969,6 +969,41 @@ class PurchaseTradeTestCase(ModuleTestCase):
         fee_model.save.assert_not_called()
         product_model.get_by_name.assert_not_called()
 
+    def test_shipment_started_cancel_deletes_draft_stock_account_moves(self):
+        'started shipment cancel removes draft account moves linked to stock moves'
+        ShipmentIn = Pool().get('stock.shipment.in')
+        draft_move = Mock(state='draft')
+        account_move = Mock()
+        account_move.search.return_value = [draft_move]
+        stock_moves = [Mock(id=10), Mock(id=20)]
+
+        with patch('trytond.modules.purchase_trade.stock.Pool') as PoolMock:
+            PoolMock.return_value.get.return_value = account_move
+
+            ShipmentIn._delete_draft_account_moves_for_stock_moves(stock_moves)
+
+        account_move.search.assert_called_once_with([
+            ('origin', 'in', ['stock.move,10', 'stock.move,20']),
+            ])
+        account_move.delete.assert_called_once_with([draft_move])
+
+    def test_shipment_started_cancel_refuses_posted_stock_account_moves(self):
+        'started shipment cancel is blocked by posted stock account moves'
+        ShipmentIn = Pool().get('stock.shipment.in')
+        posted_move = Mock(state='posted', rec_name='STJ/1')
+        account_move = Mock()
+        account_move.search.return_value = [posted_move]
+
+        with patch('trytond.modules.purchase_trade.stock.Pool') as PoolMock:
+            PoolMock.return_value.get.return_value = account_move
+
+            with self.assertRaises(UserError):
+                ShipmentIn._delete_draft_account_moves_for_stock_moves([
+                    Mock(id=10),
+                    ])
+
+        account_move.delete.assert_not_called()
+
     @with_transaction()
     def test_shipment_in_type_detects_dropship(self):
         'shipment type is dropship from supplier directly to customer'