diff --git a/waltz-data/src/main/java/org/finos/waltz/data/logical_flow/LogicalFlowDao.java b/waltz-data/src/main/java/org/finos/waltz/data/logical_flow/LogicalFlowDao.java
index ff4e9531e9..d43a03d6e1 100644
--- a/waltz-data/src/main/java/org/finos/waltz/data/logical_flow/LogicalFlowDao.java
+++ b/waltz-data/src/main/java/org/finos/waltz/data/logical_flow/LogicalFlowDao.java
@@ -109,6 +109,7 @@ public class LogicalFlowDao {
 
         return ImmutableLogicalFlow.builder()
                 .id(record.getId())
+                .externalId(Optional.ofNullable(record.getExternalId()))
                 .source(ImmutableEntityReference.builder()
                         .kind(EntityKind.valueOf(record.getSourceEntityKind()))
                         .id(record.getSourceEntityId())
diff --git a/waltz-model/src/main/java/org/finos/waltz/model/logical_flow/LogicalFlow.java b/waltz-model/src/main/java/org/finos/waltz/model/logical_flow/LogicalFlow.java
index 631398452b..682f2397af 100644
--- a/waltz-model/src/main/java/org/finos/waltz/model/logical_flow/LogicalFlow.java
+++ b/waltz-model/src/main/java/org/finos/waltz/model/logical_flow/LogicalFlow.java
@@ -31,6 +31,7 @@ public abstract class LogicalFlow implements
         CreatedUserTimestampProvider,
         EntityLifecycleStatusProvider,
         IdProvider,
+        ExternalIdProvider,
         ProvenanceProvider,
         LastUpdatedProvider,
         LastAttestedProvider,
diff --git a/waltz-schema/src/main/resources/liquibase/db.changelog-1.58.xml b/waltz-schema/src/main/resources/liquibase/db.changelog-1.58.xml
new file mode 100644
index 0000000000..0c0c23e8e4
--- /dev/null
+++ b/waltz-schema/src/main/resources/liquibase/db.changelog-1.58.xml
@@ -0,0 +1,37 @@
+<!--
+  ~ Waltz - Enterprise Architecture
+  ~ Copyright (C) 2016, 2017, 2018, 2019 Waltz open source project
+  ~ See README.md for more information
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific
+  ~
+  -->
+<databaseChangeLog xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+                   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.4.xsd"
+                   logicalFilePath="db.changelog-1.58.xml">
+    <changeSet id="v1-57-tag"
+               author="OscarGreen03">
+        <tagDatabase tag="v1.57"/> <!-- tag the current db version, i.e. the last  -->
+    </changeSet>
+
+    <changeSet id="20240119-6944-1"
+               author="OscarGreen03">
+        <comment>6944: add external_id to logical_flow table</comment>
+        <addColumn tableName="logical_flow">
+            <column name="external_id"
+                    type="${external-id.type}">
+                <constraints nullable="true" unique="true"/>
+            </column>
+        </addColumn>
+    </changeSet>
+</databaseChangeLog>
\ No newline at end of file
diff --git a/waltz-schema/src/main/resources/liquibase/db.changelog-master.xml b/waltz-schema/src/main/resources/liquibase/db.changelog-master.xml
index 6850de6aa3..34d272d9cf 100644
--- a/waltz-schema/src/main/resources/liquibase/db.changelog-master.xml
+++ b/waltz-schema/src/main/resources/liquibase/db.changelog-master.xml
@@ -201,4 +201,7 @@
     <include file="db.changelog-1.57.xml"
              relativeToChangelogFile="true"/>
 
+    <include file="db.changelog-1.58.xml"
+                relativeToChangelogFile="true"/>
+
 </databaseChangeLog>
\ No newline at end of file