The first EF6 Code key is not automatically incremented

I have this cool model:

public class Results
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public int GameId { get; set; }
    public Games Game { get; set; }
    public string Notes { get; set; }
    public virtual ICollection<ResultItems> ResultItems { get; set; }
}

      

        
        
        
      

    

For some reason, the Id field doesn't get auto increment according to the schema:

CREATE TABLE [dbo].[Results] 
(
    [Id]     INT            NOT NULL,
    [GameId] INT            NOT NULL,
    [Notes]  NVARCHAR (MAX) NULL,

    CONSTRAINT [PK_dbo.Results] PRIMARY KEY CLUSTERED ([Id] ASC),
    CONSTRAINT [FK_dbo.Results_dbo.Games_GameId] 
        FOREIGN KEY ([GameId]) REFERENCES [dbo].[Games] ([Id]) ON DELETE CASCADE
);
GO

CREATE NONCLUSTERED INDEX [IX_GameId] ON [dbo].[Results]([GameId] ASC);

      

        
        
        
      

    

I also added:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
        modelBuilder.Entity<Results>().HasKey(p => p.Id).Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        base.OnModelCreating(modelBuilder);
}

      

        
        
        
      

    

into my db context, but still the migration doesn't automatically increment this field. Can anyone see where I am doing something wrong?

Thank.

Paul.