diff --git a/GPy/kern/linear.py b/GPy/kern/linear.py
index 89e87314..d36e40b7 100644
--- a/GPy/kern/linear.py
+++ b/GPy/kern/linear.py
@@ -28,6 +28,9 @@ class linear(kernpart):
             self.Nparam = 1
             self.name = 'linear'
             if variances is not None:
+                if isinstance(variances, float):
+                    variances = np.array([variances])
+                    
                 assert variances.shape == (1,)
             else:
                 variances = np.ones(1)