The cost of train or airfares for business-related journeys is allowable. Additional costs such as excess baggage claims are also allowable if they are incurred in the performance of your duties and have no personal element.
Allowable travel costs include bridge, tunnel and road tolls, bus and taxi fares, car-parking charges and congestion charges provided they have been incurred on a business trip. The cost of overseas travel is allowable where you are obliged to incur the expense in the performance of your duties.