Partnerships - general notes: formation
A partnership may exist without a written agreement. If a later written agreement gives formal expression to an oral agreement already existing, the date of the formation of the partnership remains the date on which the terms of the oral agreement were implemented.
Where, however, a written agreement creates a partnership where none exists already, it is effective only from the date of execution and implementation of the written agreement. It has no retrospective effect. Partnership agreements were held not to have retrospective effect in Ayrshire Pullman Motor Services & Ritchie v CIR  14TC754, Waddington v O’Callaghan  16TC187, and Saywell and others (trading as Eaton Tractor Co) v Pope  53TC40.