I have a friend that have to go to court in london but it is not in england any more, can have problems??

The transport police catch my friend with a senior travel card (for retired people)that he found in the street and was using because he didnt have money to buy a oyster. Now they are asking him to go to court but it is not in england any more and is not going to go, this can cause him problems in the future if he wants to come to england or in europe??