Document:

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                                                                 EXHIBIT 4.30(a)

                                                                  EXECUTION COPY

                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

     AMENDMENT (this "Amendment") dated as of November __, 2000 is by and
between Verizon Communications Inc., a Delaware corporation formerly known as
Bell Atlantic Corporation ("Verizon"), and NTL Incorporated, a Delaware
corporation (the "Company"). All capitalized terms used herein and not otherwise
defined herein shall have the respective meanings provided to such terms in the
Registration Rights Agreement referred to below.

                              W I T N E S S E T H:
                              --------------------

     WHEREAS, Verizon and the Company are Parties to a Registration Rights
Agreement dated as of February 2, 2000 (the "Registration Rights Agreement");

     WHEREAS, the Parties to the Registration Rights Agreement desire to amend
the Registration Rights Agreement to modify certain provisions;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Verizon and the Company hereby
agree as follows:

1.   Section 2.1(b) of the Registration Rights Agreement is hereby amended as
     follows:

     (a)  To delete "December 1, 2000" in the second sentence thereof and insert
          "April 1, 2001" in its place; and

     (b)  To delete "March 1, 2001" in the second sentence thereof and insert
          "July 1, 2001" in its place.

2.   As amended hereby, the Registration Rights Agreement is hereby ratified and
     confirmed to be in full force and effect.

3.   This Amendment shall be governed, construed and enforced in accordance with
     the laws of New York applicable to contracts made and to be performed
     therein.

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4.   This Amendment may be signed in two or more counterparts, each of which
     shall be an original, with the same effect as if the signatures thereto and
     hereto were upon the same instrument.

                           [Signature Page to Follow]

<PAGE>   3

 IN WITNESS WHEREOF, each of the Parties hereto has caused this Amendment to be
 duly executed as of the date first set forth above.

                                              Verizon Communications Inc.

                                              By:______________________________
                                                  Name:
                                                 Title:

                                              NTL Incorporated

                                              By:______________________________
                                                  Name:
                                                 Title:<PAGE>   1

                                                                 EXHIBIT 4.30(b)

                                                                  EXECUTION COPY

                SECOND AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

     AMENDMENT (this "Amendment") dated as of March __, 2001 is by and between
Verizon Communications Inc., a Delaware corporation formerly known as Bell
Atlantic Corporation ("Verizon"), and NTL Incorporated, a Delaware corporation
(the "Company"). All capitalized terms used herein and not otherwise defined
herein shall have the respective meanings provided to such terms in the
Registration Rights Agreement referred to below.

                              W I T N E S S E T H:
                              --------------------

     WHEREAS, Verizon and the Company are Parties to a Registration Rights
Agreement dated as of February 2, 2000, as amended as of November 30, 2000, (the
"Registration Rights Agreement");

     WHEREAS, the Parties to the Registration Rights Agreement desire to amend
the Registration Rights Agreement to modify certain provisions;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Verizon and the Company hereby
agree as follows:

1.   Section 2.1(b) of the Registration Rights Agreement is hereby amended to
     delete "April 1, 2001" in the second sentence thereof and insert "May 1,
     2001" in its place.

2.   As amended hereby, the Registration Rights Agreement is hereby ratified and
     confirmed to be in full force and effect.

3.   This Amendment shall be governed, construed and enforced in accordance with
     the laws of New York applicable to contracts made and to be performed
     therein.

4.   This Amendment may be signed in two or more counterparts, each of which
     shall be an original, with the same effect as if the signatures thereto and
     hereto were upon the same instrument.

                           [Signature Page to Follow]

<PAGE>   2

 IN WITNESS WHEREOF, each of the Parties hereto has caused this Amendment to be
 duly executed as of the date first set forth above.

                                            Verizon Communications Inc.

                                            By:______________________________
                                                Name:
                                               Title:

                                            NTL Incorporated

                                            By:______________________________
                                                Name:
                                               Title:<PAGE>   1
                                                                 EXHIBIT 4.30(c)

                                                                  EXECUTION COPY

                THIRD AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

     AMENDMENT (this "Amendment") dated as of June __, 2001, is by and between
Verizon Communications Inc., a Delaware corporation formerly known as Bell
Atlantic Corporation ("Verizon"), and NTL Incorporated, a Delaware corporation
(the "Company"). All capitalized terms used herein and not otherwise defined
herein shall have the respective meanings provided to such terms in the
Registration Rights Agreement referred to below.

                              W I T N E S S E T H:
                              --------------------

     WHEREAS, Verizon and the Company are Parties to a Registration Rights
Agreement dated as of February 2, 2000, as amended as of November 30, 2000 and
as of March 31, 2001 (the "Registration Rights Agreement");

     WHEREAS, the Parties to the Registration Rights Agreement desire to amend
the Registration Rights Agreement to modify certain provisions;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Verizon and the Company hereby
agree as follows:

1.   Section 2.1(b) is hereby amended by adding at the end of the first sentence
     thereof, after the word "Statement", the words "as soon as reasonably
     practicable following receipt of written notice from Bell Atlantic pursuant
     to Section 2.1(c)." Section 2.1(b) is hereby further amended by deleting
     the words "by May 1, 2001" appearing in the second sentence thereof.
     Section 2.1(b) is hereby further amended by deleting the words "no later
     than July 1, 2001" appearing in the second sentence thereof and inserting
     in place thereof the words "as soon as reasonably practicable". Section
     2.1(b) is hereby further amended by deleting the last sentence thereof in
     its entirety.

2.   Section 2.1 is hereby amended by adding a new Section 2.1(c), which reads
     as follows:

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          "(c) Notwithstanding the provisions of Section 2.1(b), the obligation
     of the Company to use its best efforts to file or confidentiality submit
     the Exchangeable Registration Statement shall arise only if the Bell
     Atlantic has determined in good faith, and given to the Company written
     notice of such determination that such Exchangeable Registration Statement
     is then required as a result of: (i) the interpretation by the SEC of the
     Securities Act and/or the regulations promulgated thereunder; or (ii) any
     change in, or amendment to, the Securities Act and/or the regulations
     promulgated thereunder."

3.   Section 2.1 is hereby amended by adding a new Section 2.1(d), which reads
     as follows:

          "(d) The Company hereby covenants that, during the period beginning on
     the date hereof and ending not earlier than May 31, 2002, it will timely
     file any and all reports required to be filed by it under the Securities
     Act and the Exchange Act or otherwise publicly provide such information as
     may be necessary for the Company to meet the requirements of paragraph (c)
     of Rule 144 so as to enable Verizon to resell Registerable Securities
     without registration under the Securities Act pursuant to the exemption
     provided by (i) Rule 145(d)(2) under the Securities Act, as such Rule may
     be amended from time to time, or (ii) any similar Rule or Regulation
     hereafter adopted by the SEC."

4.   As amended hereby, the Registration Rights Agreement is hereby ratified and
     confirmed to be in full force and effect.

5.   This Amendment shall be governed, construed and enforced in accordance with
     the laws of New York applicable to contracts made and to be performed
     therein.

6.   This Amendment may be signed in two or more counterparts, each of which
     shall be an original, with the same effect as if the signatures thereto and
     hereto were upon the same instrument.

                           [Signature Page to Follow]

<PAGE>   3

 IN WITNESS WHEREOF, each of the Parties hereto has caused this Amendment to be
 duly executed as of the date first set forth above.

                                           Verizon Communications Inc.

                                           By:______________________________
                                               Name:
                                              Title:

                                           NTL Incorporated

                                           By:______________________________
                                               Name:
                                              Title:

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