Slow SQL SP execution

Another one driving me mad!!!

Why does this stored procedure take up to 20 seconds to run?

create procedure procRebookPerson
      (@Booking_ID int = null,
      @Person_ID int = null,
      @New_Booking_ID int = null,
      @User varchar(3))

with encryption

as

set nocount on

Declare @Check_in_required bit, @Checked_in bit, @Checked_in_by varchar(3), @Checked_in_on datetime, @Job_ID as int

Set @Check_in_required = 1
Set @Checked_in = 0
Set @Checked_in_by = Null
Set @Checked_in_on = Null

Select @Job_ID = Job_ID from TBL_Bookings where Booking_ID = @Booking_ID

Select @Check_in_required = check_in_required from TBL_Jobs where Job_ID = @Job_ID

If @Check_in_required = 0
      begin
      Set @Checked_in = 1
      Set @Checked_in_by = @User
      Set @Checked_in_on = getdate()
      end

INSERT INTO TBL_Placements (
      Office_ID,
      Company_ID,
      Site_ID,
      Job_ID,
      Booking_ID,
      Person_ID,
      Mon_Start,
      Mon_end,
      Tue_start,
      Tue_end,
      Wed_start,
      Wed_end,
      Thu_start,
      Thu_end,
      Fri_start,
      Fri_end,
      Sat_start,
      Sat_end,
      Sun_start,
      Sun_end,
      Pay_rate_standard,
      Pay_rate_overtime,
      Pay_rate_evening,
      Pay_rate_Saturday,
      Pay_rate_Sunday,
      Placement_notes,
      Added_by,
      Added_on,
      Checked_in,
      Checked_in_by,
      Checked_in_on
      )
Select      Office_ID,
      Company_ID,
      Site_ID,
      Job_ID,
      @New_Booking_ID,
      Person_ID,
      Mon_start,
      Mon_end,
      Tue_start,
      Tue_end,
      Wed_start,
      Wed_end,
      Thu_start,
      Thu_end,
      Fri_start,
      Fri_end,
      Sat_start,
      Sat_end,
      Sun_start,
      Sun_end,
      Pay_rate_standard,
      Pay_rate_overtime,
      Pay_rate_evening,
      Pay_rate_Saturday,
      Pay_rate_Sunday,
      Placement_notes,
      @User,
      Getdate(),
      @Checked_in,
      @Checked_in_by,
      @Checked_in_on

from      TBL_Placements where Booking_ID = @Booking_ID and Person_ID = @Person_ID




Sorry it is so long!

All it is doing is creating a new record in TBL_Placements based on an exisitng record and changing a few details, I mean, how long can it take??? lol

Anyway, anything I can check or suggestions please?


Thanks.