diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 44e6da8b..37130e82 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,7 +1,7 @@
 [bumpversion]
 commit = True
 tag = True
-current_version = 1.5.25
+current_version = 1.5.27
 message = Bump version: {current_version} → {new_version} [skip ci]
 
 [bumpversion:file:src/main.py]
diff --git a/src/gsp.py b/src/gsp.py
index 9d9497fe..663cc9c1 100644
--- a/src/gsp.py
+++ b/src/gsp.py
@@ -1,4 +1,5 @@
 """Get GSP boundary data from eso """
+import os
 from typing import List, Optional, Union
 
 import structlog
@@ -29,6 +30,7 @@
 
 
 logger = structlog.stdlib.get_logger()
+adjust_limit = float(os.getenv("ADJUST_MW_LIMIT", 0.0))
 
 
 router = APIRouter()
@@ -183,6 +185,11 @@ def get_forecasts_for_a_specific_gsp(
         creation_utc_limit=creation_limit_utc,
     )
 
+    if gsp_id == 0:
+        forecast_values_for_specific_gsp = [
+            f.adjust(limit=adjust_limit) for f in forecast_values_for_specific_gsp
+        ]
+
     logger.debug("Got forecast values for a specific gsp.")
 
     return forecast_values_for_specific_gsp
diff --git a/src/main.py b/src/main.py
index e6ccca09..fa76f9f9 100644
--- a/src/main.py
+++ b/src/main.py
@@ -42,7 +42,7 @@
 folder = os.path.dirname(os.path.abspath(__file__))
 
 title = "Quartz Solar API"
-version = "1.5.25"
+version = "1.5.27"
 
 sentry_sdk.init(
     dsn=os.getenv("SENTRY_DSN"),
diff --git a/src/tests/test_gsp.py b/src/tests/test_gsp.py
index 57f38f7f..9a6b4111 100644
--- a/src/tests/test_gsp.py
+++ b/src/tests/test_gsp.py
@@ -40,6 +40,25 @@ def test_read_latest_one_gsp(db_session, api_client):
     _ = [ForecastValue(**f) for f in response.json()]
 
 
+@freeze_time("2022-01-01")
+def test_read_latest_one_gsp_national(db_session, api_client):
+    """Check main solar/GB/gsp/{gsp_id}/forecast route works"""
+
+    forecasts = make_fake_forecasts(
+        gsp_ids=list(range(0, 2)), session=db_session, add_latest=True, model_name="blend"
+    )
+    db_session.add_all(forecasts)
+    db_session.commit()
+
+    app.dependency_overrides[get_session] = lambda: db_session
+
+    response = api_client.get("/v0/solar/GB/gsp/0/forecast")
+
+    assert response.status_code == 200
+
+    _ = [ForecastValue(**f) for f in response.json()]
+
+
 def test_read_latest_one_gsp_filter_creation_utc(db_session, api_client):
     """Check main solar/GB/gsp/{gsp_id}/forecast route works"""