D J Cooper and Partners was formed as a partnership to provide services to one customer.  The customer was a limited company which traded as a builders merchants.  The partners were also shareholders / directors of the limited company.
HMRC challenged the tax treatment of cars which were owned by the partnership and used by the partners (who were also directors of the limited company).  HMRC said that the directors of the limited company should have declared a benefit in kind for usage of the cars which they said were provided because of their office.
The tribunal case hinged on the commerciality of the arrangements and the court held that the partnership was wholly dependent on the company.  This structure would not have existed without the connection and the partnership was seen as an attempt to avoid paying tax on what was primarily a personal benefit.