bchavez · JohnStabler · Jul 13, 2023 · Dec 19, 2023 · Dec 19, 2023 · Jan 10, 2024
diff --git a/README.md b/README.md
@@ -521,6 +521,7 @@ In the examples above, all three alternative styles of using **Bogus** produce t
 	* `Bogus.DataSets.Finance.SortCode()` - Banking Sort Code
 	* `Bogus.DataSets.Finance.Nino()` - National Insurance Number
 	* `Bogus.DataSets.Address.CountryOfUnitedKingdom()` - Country of the United Kingdom
+  * `Bogus.Person.NHSNumber()` - UK National Health Service Number
 * **`using Bogus.Extensions.UnitedStates;`**
 	* `Bogus.Person.Ssn()` - Social Security Number
 	* `Bogus.DataSets.Company.Ein()` - Employer Identification Number

diff --git a/Source/Bogus/Extensions/UnitedKingdom/ExtensionsForUnitedKingdom.cs b/Source/Bogus/Extensions/UnitedKingdom/ExtensionsForUnitedKingdom.cs
@@ -1,5 +1,6 @@
 using Bogus.Bson;
 using Bogus.DataSets;
+using System.Xml.Schema;
 
 namespace Bogus.Extensions.UnitedKingdom
 {
@@ -16,7 +17,7 @@ public static string SortCode(this Finance finance, bool includeSeparator = true
          const string withSeparator = "##-##-##";
          const string withoutSeparator = "######";
 
-         if( includeSeparator )
+         if (includeSeparator)
          {
             return finance.Random.ReplaceNumbers(withSeparator);
          }
@@ -29,7 +30,7 @@ public static string SortCode(this Finance finance, bool includeSeparator = true
       /// </summary>
       public static string Nino(this Finance finance, bool includeSeparator = true)
       {
-         const string valid1stPrefixChars =   "ABCEGHJKLMNOPRSTWXYZ";
+         const string valid1stPrefixChars = "ABCEGHJKLMNOPRSTWXYZ";
          //const string valid2ndPrefixChars = "ABCEGHJKLMN PRSTWXYZ";
          const string validSuffixChars = "ABCD";
 
@@ -68,5 +69,44 @@ public static string CountryOfUnitedKingdom(this Address address)
          var countries = Database.Get(nameof(address), "uk_country", "en_GB") as BArray;
          return address.Random.ArrayElement(countries);
       }
+
+      /// <summary>
+      /// National Health Service Number
+      /// </summary>
+      /// <param name="person"></param>
+      /// <returns></returns>
+      public static string NHSNumber(this Person person)
+      {
+         string generatedDigits;
+         bool valid;
+
+         do
+         {
+            generatedDigits = person.Random.ReplaceNumbers("#########");
+            valid = true;
+
+            int sum = 0;
+            for (int i = 0; i < generatedDigits.Length; i++)
+            {
+               int digit = int.Parse(generatedDigits[i].ToString());
+               sum += digit * (10 - i);
+            }
+
+            int checkDigit = 11 - (sum % 11);
+
+            if (checkDigit == 11)
+               checkDigit = 0;
+
+            if (checkDigit == 10) // This NHS number is invalid and cannot exist
+               valid = false;
+            else
+               generatedDigits += checkDigit.ToString();
+
+         } while (!valid);
+
+         return generatedDigits;
+
+      }
+
    }
 }