SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                 SCHEDULE 13G
                                 (Rule 13d-102)


             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)

                               (Amendment No. )(1)


                                  Innospec Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    45768S105
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                December 31, 2005
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)


     Check the appropriate box to designate the rule pursuant to which this

Schedule is filed:

                [X]  Rule 13d-1(b)

                [_]  Rule 13d-1(c)

                [_]  Rule 13d-1(d)


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(1)  The remainder of this cover page shall be filled out for a reporting
     person's initial filing on this form with respect to the subject class of
     securities,  and for any subsequent amendment containing  information which
     would alter the disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
     deemed to be "filed" for the purpose of Section 18 of the Securities
     Exchange Act of 1934 or otherwise subject to the liabilities of that
     section of the Act but shall be subject to all other provisions of the Act
     (however, see the Notes).



CUSIP No. 45768S105

1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Prospector Partners, L.L.C.

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                      (a)  [_]
                                                                      (b)  [X]
3.   SEC USE ONLY


4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.   SOLE VOTING POWER


6.   SHARED VOTING POWER

     1,305,000*

7.   SOLE DISPOSITIVE POWER


8.   SHARED DISPOSITIVE POWER

     1,305,000*

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,305,000

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
                                                                            [_]

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     10.5%

12.  TYPE OF REPORTING PERSON*

     CO, IA

--------------------------------------------------------------------------------
* The Reporting Person shares investment discretion over the shares with White
Mountains Advisors LLC, pursuant to a sub-advisory agreement between Prospector
Partners, L.L.C. and White Mountains Advisors LLC. White Mountain Advisors LLC
has filed a separate Schedule 13G with respect to the Shares.



CUSIP No.   45768S105

Item 1(a).  Name of Issuer:

            Innospec Inc.
            --------------------------------------------------------------------

Item 1(b).  Address of Issuer's Principal Executive Offices:

            Innospec Manufacturing Park,
            PO Box 17
            Ellesmere Port
            Cheshire, CH65 4HF
            United Kingdom
            --------------------------------------------------------------------
Item 2(a).  Name of Persons Filing:

            Prospector Partners, L.L.C.
            --------------------------------------------------------------------

Item 2(b).  Address of Principal Business Office, or if None, Residence:

            370 Church Street
            Guilford, CT 06437
            --------------------------------------------------------------------

Item 2(c).  Citizenship:

            Prospector Partners, L.L.C.: Delaware Limited Liability Company
            --------------------------------------------------------------------

Item 2(d).  Title of Class of Securities:

            Common Stock
            --------------------------------------------------------------------

Item 2(e).  CUSIP Number:

            45768S105
            --------------------------------------------------------------------

Item 3.     If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b)
            or (c), Check Whether the Person Filing is a:

     (a)  [_]  Broker or dealer registered under Section 15 of the Exchange Act.

     (b)  [_]  Bank as defined in Section 3(a)(6) of the Exchange Act.

     (c)  [_]  Insurance  company as defined in Section 3(a)(19) of the Exchange
               Act.

     (d)  [_]  Investment  company  registered under Section 8 of the Investment
               Company Act.

     (e)  [X]  An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

     (f)  [_]  An employee  benefit plan or endowment  fund in  accordance  with
               Rule 13d-1(b)(1)(ii)(F);

     (g)  [_]  A parent  holding  company or control  person in accordance  with
               Rule 13d-1(b)(1)(ii)(G);

     (h)  [_]  A savings  association  as defined in Section 3(b) of the Federal
               Deposit Insurance Act;

     (i)  [_]  A  church  plan  that  is  excluded  from  the  definition  of an
               investment  company  under  Section  3(c)(14)  of the  Investment
               Company Act;

     (j)  [_]  Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

Item 4.  Ownership.

     Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

     (a)  Amount beneficially owned:

          1,305,000 shares deemed to be owned by Prospector Partners, L.L.C.
          ----------------------------------------------------------------------

     (b)  Percent of class:

          10.5% deemed to be owned by Prospector Partners, L.L.C.
          ----------------------------------------------------------------------

     (c)  Number of shares as to which such person has:

          (i)   Sole power to vote or to direct the vote
                Prospector Partners, L.L.C.: 0 shares

          (ii)  Shared power to vote or to direct the vote
                Prospector Partners, L.L.C.: 1,305,000 shares*

          (iii) Sole power to dispose or to direct the disposition of
                Prospector Partners, L.L.C.: 0 shares

          (iv)  Shared power to dispose or to direct the disposition of
                Prospector Partners, L.L.C.: 1,305,000 shares*
          ----------------------------------------------------------------------

* The Reporting Person shares investment discretion over the shares with White
Mountains Advisors LLC, pursuant to a sub-advisory agreement between Prospector
Partners, L.L.C. and White Mountains Advisors LLC. White Mountain Advisors LLC
has filed a separate Schedule 13G with respect to the Shares.

Item 5.  Ownership of Five Percent or Less of a Class.

     If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities check the following [ ].

         N/A
         -----------------------------------------------------------------------

Item 6.  Ownership of More Than Five Percent on Behalf of Another Person.

     If any other person is known to have the right to receive or the power to
direct the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified.  A listing of the shareholders of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employee benefit plan, pension fund or endowment fund is not required.

     The Reporting Person shares investment discretion over the shares with
White Mountains Advisors LLC, pursuant to a sub-advisory agreement between
Prospector Partners, L.L.C. and White Mountains Advisors LLC. White Mountain
Advisors LLC has filed a separate Schedule 13G with respect to the Shares.

         -----------------------------------------------------------------------

Item 7.  Identification and Classification of the Subsidiary Which Acquired the
         Security Being Reported on by the Parent Holding Company or Control
         Person.

     If a parent holding company or Control person has filed this schedule,
pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach an
exhibit stating the identity and the Item 3 classification of the relevant
subsidiary.  If a parent holding company or control person has filed this
schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating
the identification of the relevant subsidiary.

         N/A
         -----------------------------------------------------------------------

Item 8.  Identification and Classification of Members of the Group.

     If a group has filed this schedule pursuant to s.240.13d-1(b)(1)(ii)(J), so
indicate under Item 3(j) and attach an exhibit stating the identity and Item 3
classification of each member of the group. If a group has filed this schedule
pursuant to s.240.13d-1(c) or s.240.13d-1(d), attach an exhibit stating the
identity of each member of the group.

         N/A
         -----------------------------------------------------------------------

Item 9.  Notice of Dissolution of Group.

     Notice of dissolution of a group may be furnished as an exhibit stating the
date of the dissolution and that all further filings with respect to
transactions in the security reported on will be filed, if required, by members
of the group, in their individual capacity.  See Item 5.

         N/A
         -----------------------------------------------------------------------

Item 10. Certifications.

         By signing below, the reporting person certifies that, to the best of
         its knowledge and belief, the securities referred to above were
         acquired and are held in the ordinary course of business and were not
         acquired and are not held for the purpose of or with the effect of
         changing or influencing the control of the issuer of the securities
         and were not acquired and are not held in connection with or as a
         participant in any transaction having that purpose or effect.




                                    SIGNATURE

     After  reasonable  inquiry and to the best of my  knowledge  and belief,  I
certify that the information  set forth in this statement is true,  complete and
correct.

PROSPECTOR PARTNERS, L.L.C.


By:  /s/ John D. Gillespie
----------------------------------------
John D. Gillespie, Managing Member


February 14, 2006


Note.  Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
for whom copies are to be sent.

Attention.  Intentional misstatements or omissions of fact constitute federal
criminal violations (see 18 U.S.C. 1001).






SK 02081 0001 643890