'Staff Travel? Not a contractural perk I'm afraid, if it was you would have to pay tax on the benefit thus it is a management perk that can be removed if wished. Do you really want to pay tax on your staff travel tickets? You can lose your perks by upsetting those that give you the benefit. Fair? Possibly not, legal? Yep.'
We did pay tax on staff travel tickets - it changed some years ago to being taxed... Does that therefore mean it is contractual - following your argument?