This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Business Income Manual

Partnerships - computation and assessment: investment business: partner’s basis period

S847, S849, S850 Income Tax (Trading and Other Income) Act 2005

Where a partnership does not carry on a trade or profession, its income from any investment business is calculated as if the partnership was an individual, and then allocated according to the sharing arrangements in force for the relevant period of account.

But there are no special basis period rules for any such shares of income. Instead an actual (6 April to 5 April) basis of assessment applies as for individuals.