Open Question: UK tax- is a meal tax deductible?

If I hold a meeting in a restaurant with a client and pay for lunch, can it be tax deductable. Lunch is the only time we can meet and we both need to work through lunch and eat too. What's the rule here? What about a meeting in the office where we need to work through and get food in - Can this be put down as an expense - Hardly seems like 'entertainment'!