Readers’ forum: Guinea pig

My client tells me that he is taking part in a medical trial. Apparently he has received a couple of hundred pounds and will receive a higher amount for a follow-up trial. It seems that some trials can result in four-figure payments and my client is thinking of taking part in these – it appears that the medical centre is always looking for volunteers.

This makes me wonder what should be declared on the client’s tax return. Are the payments taxable or are they simply designed to cover expenses? It seems that the payments are made gross without a tax deduction. If they are taxable can for example the costs of travel to and from the medical centre be claimed and are there any other costs that might be deductible?

On the first trial my client had to follow a particular diet. Some foodstuffs were...