diff --git a/src/poetry_plugin_shell/command.py b/src/poetry_plugin_shell/command.py
index 234ac85..fb05ae6 100644
--- a/src/poetry_plugin_shell/command.py
+++ b/src/poetry_plugin_shell/command.py
@@ -28,6 +28,9 @@ class ShellCommand(EnvCommand):
     def handle(self) -> int:
         from poetry_plugin_shell.shell import Shell
 
+        if os.environ.get("POETRY_ACTIVE") == "1" and not os.environ.get("VIRTUAL_ENV"):
+            os.environ.pop("POETRY_ACTIVE")
+
         # Check if it's already activated or doesn't exist and won't be created
         if self._is_venv_activated():
             self.line(
diff --git a/tests/test_shell_command.py b/tests/test_shell_command.py
index 8b05732..264abd1 100644
--- a/tests/test_shell_command.py
+++ b/tests/test_shell_command.py
@@ -35,7 +35,9 @@ def test_shell(tester: CommandTester, mocker: MockerFixture) -> None:
 
 
 def test_shell_already_active(tester: CommandTester, mocker: MockerFixture) -> None:
+    assert isinstance(tester.command, ShellCommand)
     os.environ["POETRY_ACTIVE"] = "1"
+    os.environ["VIRTUAL_ENV"] = str(tester.command.env.path)
     shell_activate = mocker.patch("poetry_plugin_shell.shell.Shell.activate")
 
     tester.execute()
@@ -50,6 +52,23 @@ def test_shell_already_active(tester: CommandTester, mocker: MockerFixture) -> N
     assert tester.status_code == 0
 
 
+def test_shell_stale_poetry_active(
+    tester: CommandTester, mocker: MockerFixture
+) -> None:
+    assert isinstance(tester.command, ShellCommand)
+    os.environ["POETRY_ACTIVE"] = "1"
+    shell_activate = mocker.patch("poetry_plugin_shell.shell.Shell.activate")
+
+    tester.execute()
+
+    assert isinstance(tester.command, ShellCommand)
+    expected_output = f"Spawning shell within {tester.command.env.path}\n"
+
+    shell_activate.assert_called_once_with(tester.command.env)
+    assert tester.io.fetch_output() == expected_output
+    assert tester.status_code == 0
+
+
 @pytest.mark.parametrize(
     ("poetry_active", "real_prefix", "prefix", "expected"),
     [