Labour Friends of Israel chair Joan Ryan has written to Jeremy Corbyn and suggested it is “difficult to understand” how a strategy officer who once likened Israel to Isis could have been recruited to work in the Labour leader’s office.

Mark Dearn had worked as senior campaigns officer for the War On Want group for the past three years – during which time the organisation has called for sanctions on Israel and repeatedly run events attacking the country.

Mr Dearn has also previously expressed support for the BDS movement.

In her letter to Mr Corbyn, Ms Ryan, the Labour MP for Enfield North, wrote: “I am disturbed to hear that the Labour Party has hired a member of staff to the Leader of the Opposition’s office who has made comparisons between Israel and Isis.

“I find it very difficult to understand how such an appointment can be made at any time, let alone now when Labour’s antisemitism crisis is at its worst. I am concerned that this decision will be seen as deeply provocative to the Jewish community.”

Israel banned activists from War On Want – which has earned the nickname War On Israel – from entering the country over its support for BDS.

The Labour Party declined to comment.