Exhibit 5.1

                 [LETTERHEAD OF CLIFFORD CHANCE]

                                              16 October 1997



Terra Nova Insurance (UK) Holdings plc
Terra Nova House
Mincing Lane
London EC3R 7AP (the "Issuer")

Dear Sirs,

We are rendering this opinion to you in connection with an exchange offer
registration statement (on forms S-4 and F-4) which is to be filed with the
Securities and Exchange Commission ("SEC") on 15 October 1997 (the "Registration
Statement") which relates to an offer to exchange US$75,000,00 7.2% senior
guaranteed notes due 2007 which were issued by the Issuer on 26 August 1997 (the
"Old Notes) for an identical principal amount of 7.2% senior guaranteed notes
due 2007 (the "Exchange Notes").  The Exchange Notes were constituted by an
indenture dated 26 August 1997 (the "Indenture") between The Chase Manhattan
Bank, as Trustee, the Issuer and Terra Nova (Bermuda) Holdings Ltd.

We have examined copies of:

(a)   the Memorandum and Articles of Association of the Issuer confirmed by the
      secretary of the Issuer as being those now in force;

(b)   copy resolutions of the board of directors of the Issuer passed on 15
      October 1997;

(c)   an executed copy dated 26 August 1997 of the Indenture; and

 
(d)   a copy of the draft Registration Statement and the prospectus (the 
      "Prospectus") dated 14 October 1997 the final form of which is to be 
      incorporated in the Registration Statement and to be issued on 16 October 
      1997 in respect of the Exchange Notes.

Our opinion is confined solely to the laws of England.

The Indenture and the Exchange Notes are expressed to be governed by the laws of
New York.  We have made no investigation of such laws and do not express or
imply any opinions on such laws.  In addition, we have assumed that, so far as
the laws of New York are concerned, the Indenture and the Exchange Notes will
constitute legal, valid and binding obligations of the Issuer and that such laws
do not qualify or affect our opinion as set out below.

We have also assumed that:

(i)   in so far as any obligation falls to be performed in any jurisdiction
      outside England, its performance will not be illegal or ineffective by
      virtue of the laws of that jurisdiction;

(ii)  all signatures on the executed documents which, or copies of which, we
      have examined are genuine;
 
(iii) each of the parties to the Indenture, other than the Issuer, is able
      lawfully to enter into such instrument;

(iv)  the execution and delivery of the Indenture has been or, when such
      instrument is executed and delivered, will have been duly authorised,
      executed and delivered by each of the parties thereto (other than the
      Issuer);

(v)   that the Indenture has been and the Exchange Notes will be executed before
      issue of the Exchange Notes in or substantially in the form examined by us
      and in
         

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      accordance with the procedures specified in the Board Resolutions;

(vi)  the Memorandum and Articles of Association of the Issuer which we have
      examined are those now in force and the Resolution which we have examined
      were passed at a meeting duly convened and held;

(vii) the issue of the Exchange Notes will not cause any limit on borrowings to
      which the Issuer is subject to be exceeded.
               
On the basis of the foregoing, and having regard to such legal considerations as
we deem relevant and subject as set out below, we are of the opinion that:

1.    subject to paragraph 2, the Issuer is duly incorporated and validly
      existing as a public company with limited liability (having re-registered
      as a public limited company under the Companies Act 1985 on 8 June 1995)
      under the laws of England;
 
2.    We have on 14 October 1997 made a search of the Companies Registry in
      London which revealed no order or resolution for the winding-up of the
      Issuer and no order of appointment of a receiver or administrator with
      respect to the Issuer. However, the search would not reveal whether or not
      a winding-up petition has been presented. Furthermore, it is possible that
      notice of a winding up order made or resolution passed or a receiver or
      administrator appointed may not have been filed at the Companies Registry
      immediately. We have also on 14 October 1997 made enquiry of the Companies
      Court which has informed us that it has on its central index no record of
      the presentation of any winding-up petition in respect of the Issuer. We
      are assuming that there has been no change in the position since the
      searches were made.

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3.    The Issuer has all requisite corporate power to enter into the Indenture
      and to issue the Exchange Notes (including the global note) and to perform
      its obligations thereunder, the Indenture and the Exchange Notes (in the
      form of the global note) have been duly authorised, executed and delivered
      by the Issuer in accordance with the laws of England and the Memorandum
      and Articles of Association of the Issuer, and there is no reason, so far
      as English law is concerned, why the Indenture, the Exchange Notes and the
      Definitive Senior Notes (if and when they have been executed,
      authenticated and delivered as provided in the Indenture) will not
      constitute legal, valid and binding obligations of the Issuer.

The opinions expressed in paragraphs 1 to 3 inclusive above are subject to the
following:

(a)   a search at the Companies Registry is not capable of revealing whether or
      not a winding-up petition or a petition for the making of an
      administration order has been presented;
 
(b)   notice of a winding-up order or resolution, notice of an administration
      order and notice of the appointment of a receiver may not be filed at the
      Companies Registry immediately and there may be a delay in the relevant
      notice appearing on the file of the company concerned;

(c)   Nothing in this opinion shall be taken as implying that an English court
      would exercise jurisdiction in any proceedings relating to the Indenture
      or the Exchange Notes (including the global note), or accordingly that any
      remedy would be available in England for the enforcement of obligations
      arising under the Indenture or the Exchange Notes (including the global
      note). However, in our opinion, if an English court were to accept
      jurisdiction it is highly likely that the English courts would give

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      effect to the choice of New York law as the governing law of the Indenture
      and the Exchange Notes.

(d)   There could be circumstances in which an English court would not treat as
      conclusive those certificates and determinations which the Indenture and
      the Exchange Notes state are to be so treated (for example, where a
      discretion is vested in any person or a person may determine a matter in
      its opinion, if the discretion is not exercised reasonably or if the
      opinion is not based on reasonable grounds).

(e)   Our opinion as regards the binding nature and enforceability of the
      obligations of the Issuer under the Exchange Notes and the Indenture are
      subject to all limitations arising from bankruptcy, insolvency,
      liquidation, reorganisation, moratorium or similar laws affecting the
      rights of creditors generally.

(f)   Any provision in the Indenture which involves an indemnity for the costs
      of litigation is subject to the discretion of any English court (where
      relevant) to decide whether and to what extent a party to litigation
      should be awarded the costs incurred by it in connection with the
      litigation.

(g)   Except as expressly mentioned in this opinion, we have not investigated or
      verified the truth or accuracy of the information contained in the
      Registration Statement or Prospectus nor have we been responsible for
      ensuring that no material information has been omitted therefrom.

This opinion shall be construed in accordance with English law.  We express no
opinion as to any agreement, instrument or other document other than as
specified in this letter. We hereby consent to the filing of this opinion with
the SEC with and as part of the Registration Statement and to the use of our
name therein and in the Prospectus contained in

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the Registration Statement.  In giving this consent, we do not hereby admit that
we are in the category of persons whose consent is required under Section 7 of
the Securities Act of 1933 of the United States.

The above consent is given on the basis that our name is not used in any
subsequent Registration Statement (or the Prospectus contained in it) except in
an amendment or supplement to such Registration Statement, including post-
effective amendments.

This opinion is given solely for the purposes of filing the Registration
Statement and for the information of the persons to whom it is addressed and may
not be relied upon for any other purpose or by any other person.

Yours faithfully,



Clifford Chance

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