Flip through 3% stamp duty?

[SlipTheJab]

Is the three percent stamp duty on extra houses anything to worry about? I had a quick look at the rules and it seems like you can just flip your "main home" MP-style and almost completely avoid it.

For example if you are a buy-to-letter with a portfolio of half a dozen London flats and you want to spend 700,000 on another one. Instead of paying an extra (ouch) 21,000 stamp duty, can you just buy your "main" home in some godforsaken place (Wales?) where they cost 21,000. Then you move there for a couple of weeks, then buy the BTL, sell the flip-house for a nice profit, and you are the proud owner of another BTL without paying any extra tax.

Is this how it works?

Who do you think you are? an MP?

[centurian]

Okay, I finally see what you are up to. The answer is "probably, but..."

a) You would need to show you had made two house moves (council tax, utility bills etc.). Quite a bit of hassle.
b) Your credit rating would get hit with having so many house moves in a short period
b) You don't know what the HMRC rules will be around this - which might mean it has to be your primary residence for a minimum period (*) they deliberately have a bit of vagueness in them, so that they can expand the scope to deal with tricks like this.
c) It's the conveyancing solicitor that has to make the returns. If they smell a rat, they may refuse to register the sale
d) You may lose money on the £40K house - you must sell it, so you'll be forced to take
e) It's another chain which can collapse, so more expenses

(*) - I don't know why HMRC don't do this anyway for stuff like CGT - you must live in a property for at least 6 or 12 months etc.