In football, a foul caused deliberately by a player in order to stop the other side gaining an advantage they were otherwise certainly about to. (My only knowledge of this is from what follows; if you know anything about football and can correct this, let me know.)

A television play by Tom Stoppard, dealing with ethics, both in the academic sense of professional philosophers, and in the very practical sense of the repression of dissidents in a totalitarian state.

It relates to the Charter 77 movement in Czechoslovakia: in 1977 a large number of Czechoslovaks signed a petition to their own government requesting that their own laws on freedom of speech, implemented as a result of the Helsinki agreement, be adhered to. They were arrested or harassed for this. Their leading spokesperson was the playwright Vaclav Havel, who was put in gaol on trumped-up charges to separate him from the chartist movement. Stoppard's play, written for Amnesty International's "Prisoner of Conscience" Year in 1977, is dedicated to Havel, who is of course now president of the Czech Republic.

An international philosophical colloquium is being held in Prague, at the same time as a World Cup qualifying match. Anderson is a staid traditional philosopher with only a perfunctory interest in the paper he is to deliver on ethics, but a keen interest in the match. He happens to recognize a couple of the England team staying in the same hotel, and advises them on tactics he's seen the Czechoslovak players try at other matches.

McKendrick has a new theory that ethics can be related to catastrophe theory, that one's moral principles are not rigid and linear, but at certain crucial stresses must flip over and inform a different decision, one that in fact accords with our moral intuitions but not with the traditional form of the principle.

Anderson is approached by Pavel Hollar, a young man once his student, now working as a cleaner, because he is not permitted any other. Hollar wants Anderson to smuggle out a paper in which he submits, contrary to communist state doctrine, that state rights derive from individual rights. Anderson refuses, since as a guest of the country it would be impolite or even improper to do so, but when later he witnesses Hollar's flat being turned over by the secret police, and the "discovery" of black market dollars in order to have a normal criminal charge against Hollar, he goes back to his colloquium and reconsiders his options.

The title Professional Foul comes from the action his Czech hosts invoke against him to prevent his speaking freely, when Anderson incorporates ideas from Hollar into the paper he delivers. At the end of the conference, knowing he will be searched in customs, he applies McKendrick's idea of shifting the ground under basic principles, much to McKendrick's horror.

The play premièred on BBC TV in September 1977, starring Peter Barkworth as Anderson.