Expenses and vat

lgarside

Hello can someone tell me the rules with client entertaining expenses and VAT. Where I work if a partner goes out for dinner because they are having to stay over for a client they can recharge the client the gross amount plus VAT on top i.e if a meal cost 20.00 plus VAT they can charge the client 23.50 plus VAT ~ 27.61. However if the bill is for the client and the partner and the partner pays the bill, the firm is not allowed to recharge the client the gross plus vat i.e if a bill is 20.00 plus vat they can only charge the client 23.50 as oposed to 27.61. Can someone explain to me the reason why this is.

Many Thanks