diff --git a/firedrake/slate/slac/kernel_builder.py b/firedrake/slate/slac/kernel_builder.py
index d8b4b620d6..cbc9b6fed2 100644
--- a/firedrake/slate/slac/kernel_builder.py
+++ b/firedrake/slate/slac/kernel_builder.py
@@ -159,7 +159,11 @@ def collect_tsfc_kernel_data(self, mesh, tsfc_coefficients, tsfc_constants, wrap
 
         # Pick the constants associated with a Tensor()/TSFC kernel
         tsfc_constants = tuple(tsfc_constants[i] for i in kinfo.constant_numbers)
-        kernel_data.extend([(c, c.name) for c in wrapper_constants if c in tsfc_constants])
+        kernel_data.extend([
+            (constant, constant_name)
+            for constant, constant_name in wrapper_constants
+            if constant in tsfc_constants
+        ])
         return kernel_data
 
     def loopify_tsfc_kernel_data(self, kernel_data):
@@ -254,7 +258,10 @@ def collect_coefficients(self):
 
     def collect_constants(self):
         """ All constants of self.expression as a list """
-        return self.expression.constants()
+        return tuple(
+            (constant, f"c_{i}")
+            for i, constant in enumerate(self.expression.constants())
+        )
 
     def initialise_terminals(self, var2terminal, coefficients):
         """ Initilisation of the variables in which coefficients
@@ -361,9 +368,9 @@ def generate_wrapper_kernel_args(self, tensor2temp):
                                                   dtype=self.tsfc_parameters["scalar_type"])
                 args.append(kernel_args.CoefficientKernelArg(coeff_loopy_arg))
 
-        for constant in self.bag.constants:
+        for constant, constant_name in self.bag.constants:
             constant_loopy_arg = loopy.GlobalArg(
-                constant.name,
+                constant_name,
                 shape=constant.dat.cdim,
                 dtype=self.tsfc_parameters["scalar_type"]
             )
diff --git a/firedrake/slate/slac/tsfc_driver.py b/firedrake/slate/slac/tsfc_driver.py
index 34baf10dbc..0f5fbf96d3 100644
--- a/firedrake/slate/slac/tsfc_driver.py
+++ b/firedrake/slate/slac/tsfc_driver.py
@@ -59,10 +59,9 @@ def compile_terminal_form(tensor, prefix, *, tsfc_parameters=None):
     cxt_kernels = []
     assert prefix is not None
     for orig_it_type, integrals in transformed_integrals.items():
-        subkernel_prefix = prefix + "%s_to_" % orig_it_type
         form = Form(integrals)
         kernels = tsfc_compile(form,
-                               subkernel_prefix,
+                               f"{prefix}{orig_it_type}_to_",
                                parameters=tsfc_parameters,
                                split=False, diagonal=tensor.diagonal)