89Debts proving irrecoverable after event treated as discontinuance
Where section 113 or 337(1) applies to treat a trade, profession or vocation as discontinued by reason of any event, then, in computing for tax purposes the profits or gains of the trade, profession or vocation in any period after the event, there may be deducted a sum equal to any amount proved during that period to be irrecoverable in respect of any debts credited in computing for tax purposes the profits or gains for any period before the event (being debts the benefit of which was assigned to the persons carrying on the trade, profession or vocation after the event) in so far as the total amount proved to be irrecoverable in respect of those debts exceeds any deduction allowed in respect of them under section 74(j) in a computation for any period before the event.