diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp
index 091dd13752f..8fb66b1b522 100644
--- a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp
+++ b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp
@@ -190,7 +190,6 @@ void build_constraints(Builder& builder,
     }
 
     // Add block constraints
-    assign_calldata_ids<Builder>(constraint_system.block_constraints);
     for (size_t i = 0; i < constraint_system.block_constraints.size(); ++i) {
         const auto& constraint = constraint_system.block_constraints.at(i);
         create_block_constraints(builder, constraint, has_valid_witness_assignments);
diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.cpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.cpp
index d50bcd90495..7170c7a187d 100644
--- a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.cpp
+++ b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.cpp
@@ -518,6 +518,7 @@ BlockConstraint handle_memory_init(Program::Opcode::MemoryInit const& mem_init)
     // array.
     if (std::holds_alternative<Program::BlockType::CallData>(mem_init.block_type.value)) {
         block.type = BlockType::CallData;
+        block.calldata_id = std::get<Program::BlockType::CallData>(mem_init.block_type.value).value;
     } else if (std::holds_alternative<Program::BlockType::ReturnData>(mem_init.block_type.value)) {
         block.type = BlockType::ReturnData;
     }
diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.cpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.cpp
index f31501bdfda..4a81d284b5f 100644
--- a/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.cpp
+++ b/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.cpp
@@ -213,20 +213,4 @@ void process_return_data_operations(const BlockConstraint& constraint, std::vect
     ASSERT(constraint.trace.size() == 0);
 }
 
-// Do nothing for Ultra since it does not support Databus
-template <> void assign_calldata_ids<UltraCircuitBuilder>([[maybe_unused]] std::vector<BlockConstraint>& constraints) {}
-
-template <> void assign_calldata_ids<MegaCircuitBuilder>(std::vector<BlockConstraint>& constraints)
-{
-    // Assign unique ID to each calldata block constraint
-    uint32_t calldata_id = 0;
-    for (auto& constraint : constraints) {
-        if (constraint.type == BlockType::CallData) {
-            constraint.calldata_id = calldata_id++;
-        }
-    }
-    // The backend only supports 2 calldata columns
-    ASSERT(calldata_id <= 2);
-}
-
 } // namespace acir_format
\ No newline at end of file
diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.hpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.hpp
index 4fccf1d9998..a165841dbdd 100644
--- a/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.hpp
+++ b/barretenberg/cpp/src/barretenberg/dsl/acir_format/block_constraint.hpp
@@ -48,16 +48,6 @@ void process_call_data_operations(Builder& builder,
 template <typename Builder>
 void process_return_data_operations(const BlockConstraint& constraint, std::vector<bb::stdlib::field_t<Builder>>& init);
 
-/**
- * @brief Assign a unique ID to each calldata block constraint based on the order in which it was recieved
- * TODO(https://github.com/AztecProtocol/barretenberg/issues/1070): this is a workaround to allow calldata inputs to be
- * distinguished by the backend since no identifiers are received from noir.
- *
- * @tparam Builder
- * @param constraints
- */
-template <typename Builder> void assign_calldata_ids(std::vector<BlockConstraint>& constraints);
-
 template <typename B> inline void read(B& buf, MemOp& mem_op)
 {
     using serialize::read;
diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/serde/acir.hpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/serde/acir.hpp
index 74b9bb60de9..0a4d49c56fe 100644
--- a/barretenberg/cpp/src/barretenberg/dsl/acir_format/serde/acir.hpp
+++ b/barretenberg/cpp/src/barretenberg/dsl/acir_format/serde/acir.hpp
@@ -1107,6 +1107,8 @@ struct BlockType {
     };
 
     struct CallData {
+        uint32_t value;
+
         friend bool operator==(const CallData&, const CallData&);
         std::vector<uint8_t> bincodeSerialize() const;
         static CallData bincodeDeserialize(std::vector<uint8_t>);
@@ -5578,6 +5580,9 @@ namespace Program {
 
 inline bool operator==(const BlockType::CallData& lhs, const BlockType::CallData& rhs)
 {
+    if (!(lhs.value == rhs.value)) {
+        return false;
+    }
     return true;
 }
 
@@ -5604,7 +5609,9 @@ template <>
 template <typename Serializer>
 void serde::Serializable<Program::BlockType::CallData>::serialize(const Program::BlockType::CallData& obj,
                                                                   Serializer& serializer)
-{}
+{
+    serde::Serializable<decltype(obj.value)>::serialize(obj.value, serializer);
+}
 
 template <>
 template <typename Deserializer>
@@ -5612,6 +5619,7 @@ Program::BlockType::CallData serde::Deserializable<Program::BlockType::CallData>
     Deserializer& deserializer)
 {
     Program::BlockType::CallData obj;
+    obj.value = serde::Deserializable<decltype(obj.value)>::deserialize(deserializer);
     return obj;
 }
 
diff --git a/noir/noir-repo/acvm-repo/acir/codegen/acir.cpp b/noir/noir-repo/acvm-repo/acir/codegen/acir.cpp
index 232b3ba12cf..b16baf14d06 100644
--- a/noir/noir-repo/acvm-repo/acir/codegen/acir.cpp
+++ b/noir/noir-repo/acvm-repo/acir/codegen/acir.cpp
@@ -1042,6 +1042,8 @@ namespace Program {
         };
 
         struct CallData {
+            uint32_t value;
+
             friend bool operator==(const CallData&, const CallData&);
             std::vector<uint8_t> bincodeSerialize() const;
             static CallData bincodeDeserialize(std::vector<uint8_t>);
@@ -4683,6 +4685,7 @@ Program::BlockType::Memory serde::Deserializable<Program::BlockType::Memory>::de
 namespace Program {
 
     inline bool operator==(const BlockType::CallData &lhs, const BlockType::CallData &rhs) {
+        if (!(lhs.value == rhs.value)) { return false; }
         return true;
     }
 
@@ -4706,12 +4709,14 @@ namespace Program {
 template <>
 template <typename Serializer>
 void serde::Serializable<Program::BlockType::CallData>::serialize(const Program::BlockType::CallData &obj, Serializer &serializer) {
+    serde::Serializable<decltype(obj.value)>::serialize(obj.value, serializer);
 }
 
 template <>
 template <typename Deserializer>
 Program::BlockType::CallData serde::Deserializable<Program::BlockType::CallData>::deserialize(Deserializer &deserializer) {
     Program::BlockType::CallData obj;
+    obj.value = serde::Deserializable<decltype(obj.value)>::deserialize(deserializer);
     return obj;
 }
 
diff --git a/noir/noir-repo/acvm-repo/acir/src/circuit/opcodes.rs b/noir/noir-repo/acvm-repo/acir/src/circuit/opcodes.rs
index d303f9fbbab..fbd47de37b7 100644
--- a/noir/noir-repo/acvm-repo/acir/src/circuit/opcodes.rs
+++ b/noir/noir-repo/acvm-repo/acir/src/circuit/opcodes.rs
@@ -15,13 +15,13 @@ pub use memory_operation::{BlockId, MemOp};
 #[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub enum BlockType {
     Memory,
-    CallData,
+    CallData(u32),
     ReturnData,
 }
 
 impl BlockType {
     pub fn is_databus(&self) -> bool {
-        matches!(self, BlockType::CallData | BlockType::ReturnData)
+        matches!(self, BlockType::CallData(_) | BlockType::ReturnData)
     }
 }
 
@@ -183,7 +183,7 @@ impl<F: AcirField> std::fmt::Display for Opcode<F> {
             Opcode::MemoryInit { block_id, init, block_type: databus } => {
                 match databus {
                     BlockType::Memory => write!(f, "INIT ")?,
-                    BlockType::CallData => write!(f, "INIT CALLDATA ")?,
+                    BlockType::CallData(id) => write!(f, "INIT CALLDATA {} ", id)?,
                     BlockType::ReturnData => write!(f, "INIT RETURNDATA ")?,
                 }
                 write!(f, "(id: {}, len: {}) ", block_id.0, init.len())
diff --git a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/acir_gen/mod.rs b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/acir_gen/mod.rs
index 0e4bbbf759c..c93cea835ea 100644
--- a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/acir_gen/mod.rs
+++ b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/acir_gen/mod.rs
@@ -1722,10 +1722,10 @@ impl<'a> Context<'a> {
         {
             databus = BlockType::ReturnData;
         }
-        for array_id in self.data_bus.call_data_array() {
+        for (call_data_id, array_id) in self.data_bus.call_data_array() {
             if self.block_id(&array_id) == array {
                 assert!(databus == BlockType::Memory);
-                databus = BlockType::CallData;
+                databus = BlockType::CallData(call_data_id);
                 break;
             }
         }
diff --git a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/function_builder/data_bus.rs b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/function_builder/data_bus.rs
index 3cc9e19376e..6ef3d66d7e4 100644
--- a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/function_builder/data_bus.rs
+++ b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/function_builder/data_bus.rs
@@ -17,11 +17,13 @@ pub(crate) enum DatabusVisibility {
 }
 /// Used to create a data bus, which is an array of private inputs
 /// replacing public inputs
+#[derive(Clone, Debug)]
 pub(crate) struct DataBusBuilder {
     pub(crate) values: im::Vector<ValueId>,
     index: usize,
     pub(crate) map: HashMap<ValueId, usize>,
     pub(crate) databus: Option<ValueId>,
+    call_data_id: Option<u32>,
 }
 
 impl DataBusBuilder {
@@ -31,6 +33,7 @@ impl DataBusBuilder {
             map: HashMap::default(),
             databus: None,
             values: im::Vector::new(),
+            call_data_id: None,
         }
     }
 
@@ -54,6 +57,8 @@ impl DataBusBuilder {
 
 #[derive(Clone, Debug)]
 pub(crate) struct CallData {
+    /// The id to this calldata assigned by the user
+    pub(crate) call_data_id: u32,
     pub(crate) array_id: ValueId,
     pub(crate) index_map: HashMap<ValueId, usize>,
 }
@@ -75,14 +80,18 @@ impl DataBus {
                 for (k, v) in cd.index_map.iter() {
                     call_data_map.insert(f(*k), *v);
                 }
-                CallData { array_id: f(cd.array_id), index_map: call_data_map }
+                CallData {
+                    array_id: f(cd.array_id),
+                    index_map: call_data_map,
+                    call_data_id: cd.call_data_id,
+                }
             })
             .collect();
         DataBus { call_data, return_data: self.return_data.map(&mut f) }
     }
 
-    pub(crate) fn call_data_array(&self) -> Vec<ValueId> {
-        self.call_data.iter().map(|cd| cd.array_id).collect()
+    pub(crate) fn call_data_array(&self) -> Vec<(u32, ValueId)> {
+        self.call_data.iter().map(|cd| (cd.call_data_id, cd.array_id)).collect()
     }
     /// Construct a databus from call_data and return_data data bus builders
     pub(crate) fn get_data_bus(
@@ -91,9 +100,10 @@ impl DataBus {
     ) -> DataBus {
         let mut call_data_args = Vec::new();
         for call_data_item in call_data {
-            if let Some(array_id) = call_data_item.databus {
-                call_data_args.push(CallData { array_id, index_map: call_data_item.map });
-            }
+            let array_id = call_data_item.databus.expect("Call data should have an array id");
+            let call_data_id =
+                call_data_item.call_data_id.expect("Call data should have a user id");
+            call_data_args.push(CallData { array_id, call_data_id, index_map: call_data_item.map });
         }
 
         DataBus { call_data: call_data_args, return_data: return_data.databus }
@@ -136,6 +146,7 @@ impl FunctionBuilder {
         &mut self,
         values: &[ValueId],
         mut databus: DataBusBuilder,
+        call_data_id: Option<u32>,
     ) -> DataBusBuilder {
         for value in values {
             self.add_to_data_bus(*value, &mut databus);
@@ -150,7 +161,13 @@ impl FunctionBuilder {
             None
         };
 
-        DataBusBuilder { index: 0, map: databus.map, databus: array, values: im::Vector::new() }
+        DataBusBuilder {
+            index: 0,
+            map: databus.map,
+            databus: array,
+            values: im::Vector::new(),
+            call_data_id,
+        }
     }
 
     /// Generate the data bus for call-data, based on the parameters of the entry block
@@ -186,7 +203,7 @@ impl FunctionBuilder {
         let mut result = Vec::new();
         for id in databus_param.keys() {
             let builder = DataBusBuilder::new();
-            let call_databus = self.initialize_data_bus(&databus_param[id], builder);
+            let call_databus = self.initialize_data_bus(&databus_param[id], builder, Some(*id));
             result.push(call_databus);
         }
         result
diff --git a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/ssa_gen/mod.rs b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/ssa_gen/mod.rs
index 468a8573307..1373d1bc46e 100644
--- a/noir/noir-repo/compiler/noirc_evaluator/src/ssa/ssa_gen/mod.rs
+++ b/noir/noir-repo/compiler/noirc_evaluator/src/ssa/ssa_gen/mod.rs
@@ -83,8 +83,11 @@ pub(crate) fn generate_ssa(
                     _ => unreachable!("ICE - expect return on the last block"),
                 };
 
-            return_data =
-                function_context.builder.initialize_data_bus(&return_data_values, return_data);
+            return_data = function_context.builder.initialize_data_bus(
+                &return_data_values,
+                return_data,
+                None,
+            );
         }
         let return_instruction =
             function_context.builder.current_function.dfg[block].unwrap_terminator_mut();