The 'full expensing' regime has now been extended beyond the initial three-year period announced in March and will now act as a permanent UK tax break on capital investment. 

Companies that are subject to Corporation Tax can get a deduction for 100% of qualifying expenditure when they buy new, unused plant or machinery. Unincorporated businesses cannot use this deduction, but can use the AIA which gives similar benefits on investments up to £1 million a year. For "special rate" assets, companies can only get a 50% deduction for the first year and 6% for following years.

The UK full expensing regime and the super deduction are two different tax policies introduced by the UK government to encourage businesses to invest in new equipment and technology.

The UK full expensing regime allows businesses to deduct the full cost of qualifying capital assets from their taxable profits in the year they are purchased. This means that businesses can immediately offset the cost of the asset against their taxable income, rather than spreading the deduction over several years through depreciation.

The super deduction scheme that has now come to an end, allowed businesses to claim a deduction equal to 130% of the cost of qualifying capital assets against their taxable profits. This meant that businesses could deduct more than the actual cost of the asset, providing a greater tax incentive for investment.

The main difference between the two policies is the amount of tax relief they provide. While the full expensing regime allows businesses to deduct the full cost of the asset, the super deduction provided a more generous tax relief by allowing businesses to claim a deduction of 130% of the cost.