Thanks Borislav,

The table has 40 odd fields. Is that too many?

>How many fields you have in that table? If you have a relatively small number of fields you could use something like that:
>

>DECLARE @Test TABLE ( stucture as your original table except the field you want to be unique, UniqueField Ine IDENTITY(1,1))
>DECLARE @i int
>SET @i = 0
>WHILE @i < 10 && or whatever number you need to get 1.5 mil. records
>      BEGIN
>          INSERT INTO @Test (field list here EXCEPT UniqueField)
>          SELECT (field list here EXCEPT UniqueField)
>                FROM MyTable
>          SET @i = @i + 1
>      END
>INSET INTO MyTable
>SELECT (field list here EXCEPT UniqueField), CAST(UniqueField as varchar(50)) FROM @Test
>