High Court Determines 'One Signature' Bank Mandate Binds Partnership in Kotak v Kotak Case

Citation: [2017] EWHC 1821 (Ch)
Judgment on


In the case of Kotak v Kotak, the High Court of Justice, Chancery Division, addressed preliminary issues within the context of a partnership dispute involving loan agreements and the application of a bank mandate. The key topics discussed revolved around the interpretation of contractual documents, the existence of an alleged ‘one signature’ bank mandate, partnership law principles, particularly those concerning the authority of partners, and estoppel concepts.

Key Facts

The case involved two brothers, Don and Jak Kotak, who were partners in a business mainly focused on property development. Jak moved to Spain in 2002, and in his absence, Don purportedly signed several loan agreements with the Royal Bank of Scotland (RBS). Jak claimed his signature was forged on these agreements.

During the proceedings, two main issues were considered:

  1. Whether a ‘one signature’ bank mandate was in place that allowed the partnership to be bound by loan agreements signed by only one partner.
  2. Whether RBS was estopped from alleging that a signature by one partner was sufficient if the loan agreements required both signatures.

Jak also sought permission to make amendments to his claim against RBS, which revolved around whether the loans bound the partnership and whether the borrowing was for partnership purposes.

Authority of Partners (Partnership Act 1890, Section 5)

The presiding Master Bowles applied the principle from Section 5 of the Partnership Act 1890, which establishes that a partner acting within the scope of the partnership’s usual business has the actual and ostensible authority to bind the partnership. This was central to determining if the loan agreements signed by Don would bind Jak, who was also a partner.

‘One Signature’ Bank Mandate

A key document was the 1997 bank mandate, which outlined the authority given by the partnership to RBS. The court analyzed whether the mandate’s scope included authorizing Don to enter into loan agreements on behalf of the partnership with just his signature.


The court considered whether Jak was estopped from contending that the loan agreements were invalid due to the lack of both signatures. The argument centered on whether RBS, by its prior conduct, had made representations or created an understanding that would preclude it from claiming the agreements were binding with one signature.

Eiusdem Generis Rule

When interpreting the ‘one signature’ mandate, Master Bowles invoked the eiusdem generis rule, a canon of contractual interpretation that suggests when general words follow an enumeration of two or more specific things, the general words are construed as applying only to items of the same kind.

Failure of Consideration

The amendments sought to assert that if earlier loan agreements were found to be unenforceable, then subsequent refinancing agreements premised on those earlier debts would also be unenforceable due to a failure of consideration.


The court found that there was in fact a ‘one signature’ mandate in place allowing RBS to rely on Don’s signature to bind the partnership for all typical banking dealings, which included entering into loan agreements. Thus, the loan agreements signed by Don were binding on the partnership and Jak.

Concerning estoppel, there was no representation made by RBS or understanding agreed upon that loan agreements required both partners’ signatures. Jak did not place reliance on such a precondition, and hence RBS was not estopped from arguing that one signature sufficed.

The proposed amendments to broaden the arguments under Section 5 of the 1890 Act and under Section 7 concerning whether Don acted within his authority to bind the partnership were dismissed due to lack of realistic prospects for success.

Jak’s application to amend was dismissed, except for retrospective changes related to the current trial.


In Kotak v Kotak, the High Court provided a clear elucidation of partnership authority principles, specifically within the banking context. The judgment reinforces the authority of partners to bind the partnership within the usual scope of their business under Section 5 of the Partnership Act 1890 and upholds the practical approach to interpreting bank mandates. Additionally, claimants seeking to amend their claims must demonstrate realistic prospects of success, particularly in light of the court’s application of the eiusdem generis rule. The court’s decision dismisses any estoppel claim against RBS based on their alleged conduct. The case underscores the court’s focus on commercial common sense and objective standards in contractual interpretation rather than subjective understandings of the parties involved.