diff --git a/betfairlightweight/baseclient.py b/betfairlightweight/baseclient.py
index 081224ea..a456b957 100644
--- a/betfairlightweight/baseclient.py
+++ b/betfairlightweight/baseclient.py
@@ -76,7 +76,7 @@ def __init__(
         self.username = username
         self.password = password
         self.app_key = app_key
-        self.certs = certs
+        self.certs = certs or "/certs"
         self.locale = locale
         self.cert_files = cert_files
         self.lightweight = lightweight
@@ -158,10 +158,8 @@ def cert(self) -> Union[Tuple[str], str]:
         if self.cert_files is not None:
             return self.cert_files
 
-        certs = self.certs or "/certs/"
-        ssl_path = os.path.join(os.pardir, certs)
         try:
-            cert_path = os.listdir(ssl_path)
+            cert_path = os.listdir(self.certs)
         except FileNotFoundError as e:
             raise CertsError(str(e))
 
@@ -169,16 +167,16 @@ def cert(self) -> Union[Tuple[str], str]:
         for file in cert_path:
             ext = os.path.splitext(file)[-1]
             if ext in [".crt", ".cert"]:
-                cert = os.path.join(ssl_path, file)
+                cert = os.path.join(self.certs, file)
             elif ext == ".key":
-                key = os.path.join(ssl_path, file)
+                key = os.path.join(self.certs, file)
             elif ext == ".pem":
-                pem = os.path.join(ssl_path, file)
+                pem = os.path.join(self.certs, file)
         if cert and key:
             return (cert, key)
         if pem:
             return pem
-        msg = "Certificates not found in directory: '%s'" % ssl_path
+        msg = "Certificates not found in directory: '%s'" % self.certs
         hint = " (make sure .crt and .key pair or a single .pem is present)"
         raise CertsError(msg + hint)
 
diff --git a/tests/test_baseclient.py b/tests/test_baseclient.py
index f8d2a3f3..341972a8 100644
--- a/tests/test_baseclient.py
+++ b/tests/test_baseclient.py
@@ -14,7 +14,7 @@ def test_base_client_init(self):
         assert client.password == "password"
         assert client.app_key == "app_key"
         assert client.lightweight is True
-        assert client.certs is None
+        assert client.certs == "/certs"
         assert client.locale is None
         assert client._login_time is None
         assert client.session_token is None
@@ -198,13 +198,13 @@ def test_client_certs_mocked(self, mock_listdir):
             [".DS_Store", "client-2048.crt", "client-2048.key"]
         )
         assert self.client.cert == normpaths(
-            ["../fail/client-2048.crt", "../fail/client-2048.key"]
+            ["fail/client-2048.crt", "fail/client-2048.key"]
         )
 
     @mock.patch("betfairlightweight.baseclient.os.listdir")
     def test_client_single_file_cert_mocked(self, mock_listdir):
         mock_listdir.return_value = normpaths([".DS_Store", "client-2048.pem"])
-        assert self.client.cert == os.path.normpath("../fail/client-2048.pem")
+        assert self.client.cert == os.path.normpath("fail/client-2048.pem")
 
     @mock.patch("betfairlightweight.baseclient.os.listdir")
     def test_client_crt_key_preferred_over_pem_mocked(self, mock_listdir):
@@ -212,7 +212,7 @@ def test_client_crt_key_preferred_over_pem_mocked(self, mock_listdir):
             [".DS_Store", "client-2048.crt", "client-2048.key", "client-2048.pem"]
         )
         assert self.client.cert == normpaths(
-            ["../fail/client-2048.crt", "../fail/client-2048.key"]
+            ["fail/client-2048.crt", "fail/client-2048.key"]
         )