A British academic has stepped into a row over the Ben-Gurion University professor Idan Landau, whose pay was cut this week by the university because he was jailed in May for refusing to perform army reserve duty.

King's College professor Shalom Lappin joined academics from all over Israel and abroad in writing to the BGU president, Professor Rivka Carmi, to challenge the university's decision. Professor Landau has refused reserve duty for the last 11 years and has been jailed three times, but this is the first time that the university has taken any action against him.

Professor Lappin, who said he did not agree with Professor Landau's actions, nevertheless said he was "appalled" at the BGU response. He wrote: "Despite your insistence that this decision is not politically motivated, the fact that Professor Landau was singled out for this punItive action suggests that it was, in fact, a vindictive expression of political opinion, as well as a gross abuse of administrative authority. I strongly doubt that you would have penalised a faculty member who took a week off his/her academic duties to engage in political activities that you agree with.

"Nor, I suspect, would you have applied this sanction to a colleague who was absent from campus for a week in order to attend to family or personal business, and taught make up classes to compensate his/her students, as Professor Landau did."

But the university response, written by lawyer Almog Tzabar, was trenchant. It said: "Landau was not punished by the university nor did the university impose any sanctions upon him because of his political views or because the university is taking any sort of position concerning his choice not to do reserve duty.

"An employee is paid a salary for working. Since Landau was in jail, he was unable to work during his period of incarceration – and therefore is not eligible for the salary he would have earned during that period. Therefore, in accordance with solicited legal advice, it was decided to dock his salary for that period because he was not working.

"Nevertheless, above and beyond any legal requirements, since Landau did fulfil his teaching requirements, it was decided to dock 50 per cent of his salary for the time he was absent from work. Not only is this behaviour not improper, this decision reflects the university administration's cautious use of public funds."