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

HMRC internal manual

Company Taxation Manual

Income Tax: collection of tax on annual payments: date tax payable

ITA07/s949 (3)

The IT due in respect of a relevant payment is due at the time the return is due - within 14 days of the end of the return period. An assessment is not required (see, however, CTM35130).