The new rules start on 4 December 2014 – but if you’ve already exchanged on a property you’ll have a choice about whether to use the old or new rules.
Completing your sale on and after 4 December 2014
If you exchange and complete (or in Scotland, settle) your home purchase on or after 4 December you will pay stamp duty under the new rules.
Completed your sale before the 4 December 2014
If you completed on the purchase of your property on or before 3 December 2014, but have not yet filed your stamp duty return, you still have to pay stamp duty under the old rules.
Exchanged on your contract before 4 December 2014
If you exchanged contracts (or in Scotland, concluded missives) before 4 December but complete on or after that date you’ll be able to choose whether the old or new rules apply.
HM Teasury says: “In the majority of cases you will pay less tax under the new regime”