Britain’s Treasury will reduce the discount rate used to appraise public spending to 3% from 3.5%, as part of reforms intended to encourage investment in public infrastructure. The rate is set out in the Treasury’s Green Book, the manual governing approval of capital projects. A lower rate narrows the difference between costs incurred today and benefits delivered in the future, helping long-term projects demonstrate their value. Full details, including the government’s response to a review of the discount rate, are due at the budget on October 28. Finance Minister John Healey is expected to outline elements of the plan in his first major speech in the role on Monday. The Treasury is also piloting an approach that evaluates the investment potential of whole areas in Plymouth, Liverpool, Birmingham and Port Talbot rather than assessing projects individually.