diff --git a/docker/service/src/main/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapper.java b/docker/service/src/main/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapper.java
index b7a75225..d238a1ff 100644
--- a/docker/service/src/main/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapper.java
+++ b/docker/service/src/main/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapper.java
@@ -1,6 +1,7 @@
 package uk.nhs.adaptors.scr.mappings.from.hl7;
 
 import lombok.SneakyThrows;
+import org.slf4j.LoggerFactory;
 import org.hl7.fhir.r4.model.BaseDateTimeType;
 import org.hl7.fhir.r4.model.DateTimeType;
 import org.hl7.fhir.r4.model.InstantType;
@@ -106,6 +107,15 @@ static <T extends BaseDateTimeType> T parseDate(String date, Class<T> clazz) {
             baseDateTimeType.setTimeZone(TimeZone.getTimeZone(TIMEZONE));
             baseDateTimeType.setYear(parseInt(date) + 1);
             baseDateTimeType.setMillis(yearPrecision);
+        } else if (date.equals("1")) {
+            date = "19700101";
+            LocalDate parsed = LocalDate.parse(date, DateTimeFormatter.ofPattern(DATE_PATTERN));
+            baseDateTimeType.setPrecision(DAY);
+            baseDateTimeType.setTimeZone(TimeZone.getTimeZone(TIMEZONE));
+            setDatePart(baseDateTimeType, parsed.getDayOfMonth(), parsed.getMonthValue(), parsed.getYear());
+            baseDateTimeType.setMillis(dayPrecision);
+            org.slf4j.Logger logger = LoggerFactory.getLogger(XmlToFhirMapper.class);
+            logger.error("Invalid date value:1 updated");
         } else {
             throw new ScrBaseException("Unsupported date format: " + date);
         }
diff --git a/docker/service/src/test/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapperTest.java b/docker/service/src/test/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapperTest.java
index cb1ffdae..091b971a 100644
--- a/docker/service/src/test/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapperTest.java
+++ b/docker/service/src/test/java/uk/nhs/adaptors/scr/mappings/from/hl7/XmlToFhirMapperTest.java
@@ -37,6 +37,10 @@ public void When_ParsingDate_Expect_CorrectDateFormat() {
         date = parseDate("2023", InstantType.class);
         assertThat(date.getValueAsString()).isEqualTo("2023");
 
+        // FLAGSAPI-806
+        date = parseDate("1", InstantType.class);
+        assertThat(date.getValueAsString()).isEqualTo("1970-01-01");
+
         assertThrows(ScrBaseException.class, () -> {
             parseDate("-2023", InstantType.class);
         });