Tom, have you got any pictures?

I'm sure there'd be a way of getting it out, and you out of the s**t.

How good is your LBS?  No offence to them, I'm sure they know their bikes, but they may just not have the tools for such a job.

Heating as has been mentioned is probably not the best idea, as depending on the frame material it could have an adverse effect to the already heat treated frame, or at least wreck your paint.

Is there any of it to grab hold of, or is it dead flush with top of seat tube?

If there is anything to grab hold of, I'd try soaking the joint with plusgas overnight, then hold the frame secure and use some grips or something to try turning/pulling the post?  If there was anything sticking out you could get someone to weld a block to it, then try using a slide hammer?  Drill and tap the block, bit of studding, something heavy and some nuts?

Woah Terry never knew it was that much.  It's a 31.6mm post my quill stem didn't fit but the shop I took it to tried one and it didn't budge.

Andy,
Theres nothing sticking out unfortunetly, they're pretty good, it went to an engineer that they knew and he's tried tapping the seatpost and then pulling it out but to no success, plusgas I don't reckon would work as it's wedged in.  I took it to work and they tried a slide hammer but to no avail   Seems to be a case of trying to mill it out or something.  Someone recommended BETD.
TBH for £750 you'd expect it to not be in a condition like this, despite what frame it is.
No pictures as of yet it's in the shop still, I need to get it back so I can potentially send it to someone

any chance of having a thread put into the seatpost and screwing something into and pulling it out?

please note i have NO knowledge of putting thread of that size into anything before people laugh ha ha

No need to laugh it's been tried   I reckon if it could be machined out then i could leave some of it in there, as long as I have a decent amount of post in the frame it should be alright.

f**k it it pursue that someone further before it costs you an arm and a leg


at the end of the day hes quite deliberately not told you and inferred that its a shim when its quite clearly now ...

You could ream the inside of the post out, so that it does effectively become a shim- since you've got a fair length to work with, a hand reamer could be used without affecting alignment- should be a fair bit cheaper than actually setting it up on a millling machine to do what is effectively the same job. 27.2 is the most common seatpost size, so would make sense to aim for that.

Fair point; I wouldn't fancy cutting a slit in it. Nonetheless, a hand reamer could be used to remove the post outright, although care would be required in the final stages to avoid reaming the frame.

You tried the hacksaw blade approach yet?

Time consuming but doable...