Has a very significant impact on Corporation Tax
None at all.
Understand where you coming from
Depreciation policy is set by Board of directors of a company and they can set whatever policy they like........................therefore management would do everything they could to ensure high or low profits by saying Aircraft will last 25 years or 1 year and Laptops 10 or 6 months so higher / lower profits shown and they get bigger bonuses or pay less tax .
However Govts want to avoid companies doing this as would mean no idea what tax they could collect PLUS they want to incentivise businesses to invest in new technology / equipment / buildings etc as this helps the economy grow. #
So for tax calculation Depreciation is added back to profits and then the Govt give a Capital Allowance over a number of years depending of what has been invested in.
A tax accountant friend explained this down the pub over a long beer or least it felt like that............................then he said thats how he and his colleagues make money by interpreting WTF the Govt are doing on tax.