I saw this item on Ebay and it is not a published letter in The Letters of J.R.R. Tolkien, no doubts in this case that it is a genuine letter.

http://cgi.ebay.co.uk/Tolkien-Signed- ... |301%3A0|293%3A1|294%3A50

Text

PROFESSOR J.R.R. TOLKIEN
Oxford 61639

76 SANDFIELD ROAD
HEADINGTON
OXFORD
August 10th. 1964.

Dear Miss Ward,
My secretary has just discovered your letter of March 23rd. I am sorry that you have been treated with such discourtesy. I was away from March 12 to April 2, but the letter was not forwarded as it should have been. I was taken ill while away, and was out of action during April, and also without a secretary. My correspondence got into great confusion.
I am delighted to hear of your great enjoyment of my book. As for Television, however, I am personally averse to dramatizations of my work, especially of The Lord of the Rings, which is too long for reproduction without severe cutting and editing; in my view destructive, or at best severely damaging to a complicated but closely-woven story. But in such matters the interests of my publishers must be considered. They are in any case primarily concerned in all questions of reproduction by any process (vide the copyright notice).
I think they would be willing to consider proposals for television especially when the plan had proceeded at least as far as an outline of the proposed treatment. If your enthusiasm has not been chilled by my silence, or this reply, and you still think of going further with your ides (sic), I think you should approach Messrs Allen and Unwin in the first instance.
At the moment I am trying to complete work for an overdue contract, and since I am nevertheless obliged to go away till the end of this month, I shall have no time to spare for some weeks. Of course if there is a prospect of a television plan being agreed, I should desire very much to see you and consult you later.

Yours sincerely,

J.R.R. Tolkien