EmpTaxQue

We need to pay our staff allowances for when they have to stay away overnight. We were thinking of £5 personal incidental expenses plus £20 for food (£5 breakfast, £5 lunch, £10 evening meal). We would book and pay for accommodation and if any of the meals were included with the accommodation, the expense for that meal could not be claimed. Is this all covered by the benchmark rates or would we have to apply for a benchmark rate? I've watched a webinar and read the relevant sections of the employment income manual but it's still not clear to me.