There are special rules for capital expenditure, and depending on the current capital allowances rules a company will pay less corporation tax depending on the amount of capital allowances allowed.
These depend on the type of asset and the rules can change massively year on year. For example, until 31 December 2015, 100% of expenditure on equipment costing up to £500,000 a year is tax deductible, but in the recent past the maximum was as little as £25,000.. Therefore it always sensible to get up to date advice before purchasing large capital items as the timing could critically change the timing of your tax payments.
Also ensure your accountant keeps you up to date with special incentives e.g. 100% capital allowances on fuel efficient cars and other environmentally friendly equipment.
A particular issue is the purchase of land and buildings, for which no capital allowances are generally available. However, plant and machinery within a building, such as electrical and plumbing systems, can qualify, and it is important to be able to quantify these costs. When purchasing a building from a previous owner, the rules on capital allowances are especially complicated and may require the seller to enter into an election, so it is important to consider this in advance.