Best of both worlds?

I have a client with a financial year end of 31 March 2008. On 30 March the company was invoiced for and paid a fee of £25 000 to a well-known TV celebrity for doing a photo session in a studio with a range of the company's products. The photo session took place on the same date. The photos will then appear in a range of national magazines during the summer months with a caption from the celebrity endorsing the quality of the products.

My client has asked whether the £25 000 can be claimed against the company's 2008 profits for corporation tax purposes on the basis that the photo shoot took place within the 2008 financial year. However he has then asked if the expense can be treated as a prepayment for accounting purposes on the basis that the benefits to the company will not be...