Contents EIM65799 EIM66110
Tax treatment of lorry drivers: subsistence allowances paid to lorry drivers: approved amount
Where the conditions in EIM66105 are met, the following amounts should be accepted as doing no more than reimburse the expenses of accommodation and subsistence in the United Kingdom.
Year ended Payment per night
31 December 2017 £34.90
Contents EIM65799 EIM66130
Tax treatment of lorry drivers: subsistence allowances paid to lorry drivers: lorries with sleeper cabs
Where the employer is satisfied that the employee necessarily incurred expenses as a result of a night spent away from home and his or her permanent workplace (if any), HMRC accepts that a payment of 75% of the figure shown at EIM66110 does no more than reimburse the expense incurred when the driver uses their sleeper cab overnight.
75% of £34.90 = £26.175.
Quotes from links in Rich`s post