You can sue the paper and the individual involved for libel.
The test for libel is that the story must be untrue and will damage your reputation in the eyes if a right mnded member of the public.
If you do not wish to sue you can certainly demand a retraction and threaten proceedings if any similar allegations are made in the future.
I hope this helps. If there are any further points please reply
Thanks - can you recommend someone in London to represent me?
I am afraid that we cannot do that and I do not know of a particular firm that I would put above the others for this kind of case.