CTM61730 | Close companies: loans to participators: two or more close companies
From HM Revenue & Customs · Company Taxation Manual
Two or more close companies may together control a company making a loan within or ( or ). In that case each close company is to be treated for the purpose of as:
controlling the lending company
making a loan of the appropriate proportion of the loan made by that company
When deciding what is ‘appropriate’, you should consider the nature and amount of the close companies’ respective interests in the lending company.