Moving a tree in a pot

Can anyone advise me on moving my Katsura tree (Cercidiphyllum Japonicum) I've had it in a fairly small decorative glazed pot for six or seven years and in that time it's grown to about nine feet tall.It's been fine where it was but now i need to move it and of course the roots have grown out of the pot and anchored it into the soil around.
I obviuosly can't get it out of the pot so i'm wondering,if i cut the root and just move it is it likely to die or the alternative is to uproot the whole thing and replant it pot and all.
I've read that they grow up to 40 feet in America and 100 feet in their native Japan.Anyone have one here in the UK and can tell me their expected height?I've only a smallish garden.
Thanks
I've posted this again as i'm not sure i put it in the right place first time.Sorry
Posts
Hi Klink
I think you'll find the roots that are outside the pot are the most important bits for uptake of water and nutrients. I'd uproot the lot, abandon the pot (big hammer or stanley knife as appropriate) and find it a good home with the roots well spread out and some nice compost.
In the sticks near Peterborough
I have Katsura (Cercidiphyllum Japonicum). They take a pruning in autumn, so can be any size you need. I have had mine for 10 years and it is still only 8ft with a thin canopy. They do need good drainage, so make sure the new home has lots of added grit.
no more to add to what nutcutlet has already said but good luck
Thank you for your advice.I was going to try and move it today but glad i waited now
It will need a big hammer nutcutlet,the pots about two inches thick which is maybe why it hasn't burst out of it yet!
blairs, i hadn't realised it could be pruned (i'm a coward with the secateurs,meaning i stear clear of roses for fear of killing them..) Any advice on how i'd prune it to keep it around the height it is now?
My only advice is to prune in winter (after the lovely leaves have fallen) to your own preference and shape.
My 2 Katsura where the first ones to leaf this year.