diff --git a/src/blueapi/cli/scratch.py b/src/blueapi/cli/scratch.py
index 2536be404..6fa01d83e 100644
--- a/src/blueapi/cli/scratch.py
+++ b/src/blueapi/cli/scratch.py
@@ -129,22 +129,16 @@ def scratch_install(*paths: Path, timeout: float = _DEFAULT_INSTALL_TIMEOUT) ->
     """
     if not paths:
         return
-    args = [
-        "uv",
-        "pip",
-        "install",
-    ]
+    LOGGER.info("Installing packages")
     for path in paths:
         _validate_directory(path)
-        args.extend(["-e", str(path)])
-
-    LOGGER.info("Installing packages")
-    process = Popen(args)
-    process.wait(timeout=timeout)
-    if process.returncode != 0:
-        raise RuntimeError(
-            f"Failed to install packages: Exit Code: {process.returncode}"
-        )
+        args = ["uv", "pip", "install", "-e", str(path)]
+        process = Popen(args)
+        process.wait(timeout=timeout)
+        if process.returncode != 0:
+            raise RuntimeError(
+                f"Failed to install packages: Exit Code: {process.returncode}"
+            )
 
 
 def _validate_root_directory(root_path: Path, required_gid: int | None) -> None:
diff --git a/tests/system_tests/test_blueapi_system.py b/tests/system_tests/test_blueapi_system.py
index b152e966d..8c4dc19cf 100644
--- a/tests/system_tests/test_blueapi_system.py
+++ b/tests/system_tests/test_blueapi_system.py
@@ -1,4 +1,5 @@
 import inspect
+import subprocess
 import time
 from asyncio import Queue
 from collections.abc import Generator
@@ -884,3 +885,72 @@ def test_run_blocking_requires_auth(
 ):
     with pytest.raises(UnauthorisedAccessError):
         client_without_auth.run_blocking(small_task)
+
+
+# Kept last: installs packages into the environment, so it must not run
+# before (and potentially disturb) the tests above.
+@pytest.mark.timeout(600)
+@pytest.mark.parametrize(
+    "repos,expected_location_name,expected_version",
+    [
+        pytest.param(
+            [("dodal", "2.6.2"), ("dodalv3.0.0", "3.0.0")],
+            "dodalv3.0.0",
+            "3.0.0",
+            id="v2-then-v3",
+        ),
+        pytest.param(
+            [("dodalv3.0.0", "3.0.0"), ("dodal", "2.6.2")],
+            "dodal",
+            "2.6.2",
+            id="v3-then-v2",
+        ),
+    ],
+)
+def test_setup_scratch_last_repo_wins_for_duplicate_package(
+    tmp_path: Path,
+    repos: list[tuple[str, str]],
+    expected_location_name: str,
+    expected_version: str,
+):
+    """
+    Regression test for https://github.com/DiamondLightSource/blueapi/issues/1590
+
+    Two scratch repositories both provide the dls-dodal package, pinned to
+    different tags. setup-scratch installs each editable in config order, so
+    the later entry must be what is left installed.
+    """
+    scratch_root = tmp_path / "scratch"
+    scratch_root.mkdir()
+    overlay = tmp_path / "overlay.yaml"
+    repo_entries = "\n".join(
+        f"""    - name: {name}
+      remote_url: https://github.com/DiamondLightSource/dodal.git
+      target_revision: "{revision}\""""
+        for name, revision in repos
+    )
+    overlay.write_text(f"""
+scratch:
+  root: {scratch_root}
+  repositories:
+{repo_entries}
+""")
+
+    result = subprocess.run(
+        ["uv", "run", "blueapi", "-c", str(overlay), "setup-scratch"],
+        capture_output=True,
+        text=True,
+    )
+    assert result.returncode == 0, result.stdout + result.stderr
+
+    installed = subprocess.run(
+        ["uv", "run", "--no-sync", "uv", "pip", "show", "dls-dodal"],
+        capture_output=True,
+        text=True,
+    )
+    assert (
+        f"Editable project location: {scratch_root / expected_location_name}"
+        in installed.stdout
+    )
+    assert "Name: dls-dodal" in installed.stdout
+    assert f"Version: {expected_version}" in installed.stdout