The first non-Arab foreign teacher at one of the three universities in the West Bank was deported from the occupied territory today for refusing to sign a pledge that he would offer no assistance to the Palestine Liberation Organization.

Mark Cheverton, 23, a biology laboratory instructor at Bethlehem University, told a news conference here before his departure that the anti-PLO statement was "clearly political" and that forcing West Bank university teachers to sign it was "a blow to academic freedom and hence the truth."

Cheverton is a British citizen. The British consul here, Vic Henderson, said the British government had conveyed its "concern" at his deportation to the Israeli Embassy in London.

Cheverton is the 17th foreign teacher to be deported from the West Bank this fall. His expulsion indicated that Israeli authorities are prepared to act against citizens of traditionally friendly countries in enforcing the new regulation. The other 16 all taught at Najah University in Nablus and were Arabs holding Jordanian passports.

The Israeli military authorities in the West Bank announced in September that foreign nationals teaching at the universities would be required to sign the statement before being granted new work permits, and that those who refused would be deported when their present work permits expired.

The statement asks the teachers to declare that "I am committed not to do any kind of work and not to give any services directly (or indirectly) which will help or support the so-called PLO organization or any other hostile organization."

Almost none of the teachers at the universities -- Bethlehem, Najah and Bir Zeit -- have agreed to sign the statement and more than 100 of them face possible deportation.

Brother Thomas Scanlan, vice chancellor of Bethlehem University, said 10 other members of the Roman Catholic institution's 117-member academic staff, including five Americans, are directly threatened by the demand that they sign the anti-PLO pledge. He said the Vatican, which owns and operates the school, viewed the pressure being put on the foreign teachers with "the gravest concern."

Scanlan charged that the new requirement is "an attempt to politicize our universities" and formed a part of a "clear pattern of harassment by the military toward the universities."

Israeli officials have said the statement is similar to what is required of foreign nationals teaching in other countries and is an attempt to make sure the West Bank teachers clearly understand that any contact with the PLO is illegal.