Leased assets which may be purchased at the end of the lease are depreciated just as if they were owned and not leased. This is the remaining amount to be depreciated when asset was purchased from the lessor. It is different from the lease instalments which include an interest charge and a capital repayment component.


International Accounting Standard 17 - leased assets section 28
The depreciable amount of a leased asset is allocated to each accounting period during the period of expected use on a systematic basis consistent with the depreciation policy the lessee adopts for depreciable assets that are
owned. If there is reasonable certainty that the lessee will obtain ownership by the end of the lease term, the period of expected use is the useful life of the asset; otherwise the asset is depreciated over the shorter of the lease term and its useful life.

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Note added at 5 hrs (2016-05-21 19:22:47 GMT)
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I said "This is the remaining amount to be depreciated when asset was purchased from the lessor." This wrong. I was assuming that the asset had just been purchased from the leasing company. If it was purchase last year or before, then it is just the residual depreciation now.