Exhibit 8.1

 
                              September 26, 1996



Southern Investments UK plc
800 Park Avenue
Aztec West
Almondsbury
Bristol BS12 4SE, England

Dear Sirs:

     We are acting as counsel to Southern Investments UK plc (the "Company") in
connection with the preparation, authorization, execution and filing of the
Registration Statement (Reg. No. 333-09033) on Form S-1 (the "Registration
Statement") under the Securities Act of 1933, as amended, with respect to the
registration of Senior Notes of the Company (the "Senior Notes").

     We have examined originals or copies, certified or otherwise identified to
our satisfaction, of such corporate records, agreements, documents and other
instruments and such certificates or comparable documents of public officials
and representatives of the Company, and have made such other and further
investigations, as we have deemed relevant and necessary as a basis for the
opinions hereinafter set forth.

     In such examination, we have assumed the genuineness of all signatures, the
legal capacity of natural persons, the authenticity of all documents submitted
to us as originals, the conformity to original documents of all documents
submitted to us as certified or photostatic copies, and the authenticity of the
originals of such latter documents.

     Based on the foregoing, and subject to the qualifications and limitations
stated herein, we are of the opinion that the statements made in the
Registration Statement under the heading "Certain Income Tax Considerations--
U.S. Federal Income Tax Considerations," insofar as they purport to constitute
summaries of matters of certain U.S. federal income tax laws and regulations,
are confirmed in all material respects.

 
Southern Investment UK plc
September 26, 1996
Page 2
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     We are members of the Bar of the State of Georgia and we do not express any
opinion herein concerning any law other than the federal law of the United
States.

     We hereby consent to the use of our name under the caption "US Federal
Income Tax Considerations" in the Prospectus forming part of the Registration
Statement and to the filing, as an exhibit to the Registration Statement, of
this opinion.  In giving the foregoing consent, we do not hereby admit that we
come within the category of persons whose consent is required under Section 7 of
the Securities Act of 1933, as amended, or the rules and regulations of the
Commission thereunder.

     This opinion is rendered solely for your benefit in connection with the
transactions described above. This opinion may not be used or relied upon by any
other person and may not be disclosed, quoted, filed with a governmental agency
or otherwise referred to without our prior written consent, except as noted
above.

                                        Very truly yours,

                                        Troutman Sanders LLP