es which recognize such an obligation, _e.g._ a warranty
against average "unless general," or an agreement that G.A. shall be
payable "as per foreign statement," or "according to York-Antwerp Rules";
but it does not directly state the obligation. It assumes that. The
explanation seems to be that the practice of the underwriter to pay the
contribution has been so uniform, and his liability has been so fully
recognized, that express provisions were needless. But one result has been
that very differing views of the ground of the obligation have been held.
One view has been that it is covered by the sue and labour clause of an
ordinary policy, by which the insurer agrees to bear his proportion of
expenses voluntarily incurred "in and about the defence, safeguard and
recovery" of the insured subject. But that has been held to be mistaken by
the House of Lords (_Aitchison_ v. _Lohre_, 1879, 4 A.C. 755). Another view
is that the underwriter impliedly undertakes to repay sums which the law
may require the assured to pay towards averting losses which would, by the
contract, fall upon the underwriter. Expenses voluntarily incurred by the
assured with that object are expressly made repayable by the sue and labour
clause of the policy. It might well be implied that payments compulsorily
required from the assured by law for contributions to G.A., or as salvage
for services by salvors, will be undertaken or repaid by the underwriter,
the service being for his benefit. But the decision in _Aitchison_ v.
_Lohre_ negatives this ground also. The claim was against underwriters on a
ship which had been so damaged that the cost of repairs had exceeded her
insured value. A claim for the ship's contribution to certain salvage and
G.A. expenses which had been incurred, over and above the cost of repairs,
was disallowed. The view seems to have been that the insurer is liable for
salvage and G.A. payments as losses of the subject insured, and therefore
included in the sum insured, not as collateral payments made on his behalf.
This bases the claim against the insurer upon a fiction, for there has been
no loss of [v.03 p.0058] the subject insured; in fact, the payment has been
for averting such a loss. And it suggests that the insurer is not liable
for salvage where the policy is free of particular average, which does not
accord with practice.

An important question as to an insurer's liability for G.A. arose in the
case of the _Brigella_ (1893, P.