Trading losses used against non trading income

[type R]

When you have trading losses which you use against non trading income, and then carry the losses forward for Class 4 NI purposes, can be be carried forward indefinately until it is used up, or is it limited to the following year only?

Thanks in advance to any one who answers.

[Instinctive]

My understanding is that the losses are available to carry forward indefinitely and to be used against first available NIC4 profits until exhausted. The losses will need to be claimed and not become time-barred.

Ramnik