Part 2 CHARGEABLE PERIODS ENDING ON OR AFTER 1ST OR 6TH APRIL 2001 5Writing-down allowances: infrastructure from UK or non-UK oil fields 6Ring fence trades: meaning of “abandonment expenditure” 7Ring fence trades: special allowance for pre-cessation expenditure 8Ring fence trades: allowances for post-cessation expenditure 9Commencement of Part 2 Part 2