...and it has always been acceptable to the tax man.
Items bought for the business are written down as capital expenditure and become 'company assets'. That then depreciates each year (at different rates for different items) and this depreciation is tax deductible. Then, after a time - again dependent on the equipment - that value is written off.
One side-effect is that you can use the company assets for personal use. The slight exception is with a car, in which case you pay a percentage dependent on the amount of private use that the car has.
When you get your next tax return, you will see in the explanatory notes how it works in greater detail - and with worked examples that even a twit like me could follow.