VAT Question of the Week: Hotel Deposits

My client frequently has to stay in hotels for business. The hotel takes a deposit at the time of booking with the balance of the cost paid over when the stay takes place. Sometimes my client’s plans, or those of his customer, change and he cancels the booking and the hotel keeps the deposit paid. Some hotels send a VAT invoice covering the amount of the deposit they retain after the cancellation and some say that they cannot issue a VAT invoice because VAT is not applicable to the amount they have retained. Which is correct for VAT purposes?