In reply to adstapleton: Unless you intend to commission the services of a Structural Engineer; I would leave well alone! A good experienced builder should tell you this, as the only thing that will stand up in court (should the house fail to stand up at all!) will be the engineer's credentials and thier professional indemnity insurance.
Anything at all can be done right, if you have sufficient funds... such as re-building the house from scratch without a chimney.
If you do take the chimney down...
1. You may need planning consent
2. You will need building regulations certification (via full plans or a building notice) and structural calcs are likely to be required in this case.
My advice...? Put a lovely woodburner in there (or an Aga etc.). If the hearth is centre house it should be most effective in heating the thermal mass of the property.
The chimney may also be contributing to ventillation; so removal might bring condensation issues and poorer air quality - requiring other action to remediate.
Good luck