Sanctions?

Or at least stop selling them arms?

Edit: well, this is a milquetoast start

In his statement to parliament, Miliband said the UK government would enact:

An import ban on goods from illegal settlements in the occupied territories and a new ban for arms licences and other exports that “materially contribute to the occupation”

A comprehensive sanctions regime against providing services such as construction or financing for Israeli settlements and a ban on advertising them in the UK

Personal sanctions against key individuals accused of promoting settler violence.

A new ban for arms licences and other exports that “materially contribute to the occupation”.