This week I tried to enter the illegally occupied West Bank, along with two other British parliamentarians and an international delegation of observers. We were all interrogated and detained by Israeli forces for nearly eight hours and finally prevented from crossing the border.

Our unpleasant experience pales in comparison to the daily experience of Palestinians living under occupation. Year after year, decade after decade, Palestinians have faced not simply inconvenience but a systematic attempt to eradicate their existence. We have seen a genocide in its most brutal form in Gaza. But in the West Bank we see a slow-motion form of ethnic cleansing, perpetrated by Israeli forces and their settler militias.

And it gets worse. Israeli Finance Minister Bezalel Smotrich called on Israel last month to do the same in the occupied West Bank as “what we did in Gaza”. And so we came to shed light on Israel’s crimes, including the brutal attacks on olive harvesters which seek to deprive Palestinians of the livelihood that sustains them.

As the suffering inflicted on Palestinians grows ever more extreme, so Israel moves to stop the outside world from bearing witness. In the last 18 months, two British delegations of MPs have been turned away. Through three years of genocide in Gaza, Israel has killed more than 200 Palestinian journalists, with much evidence suggesting direct targeting. In the Hebron operation last week, Israeli forces used tear gas on journalists attempting to film the demolition of Palestinian homes. The message is clear: the world must not see what is happening here.

A pivotal moment Our visit, organised by Global Justice Now, came at a critical time, just before Israeli elections and shortly after the United Kingdom announced new sanctions on Israel’s illegal settlements in the West Bank. The elections have yet to produce a clear outcome, and Prime Minister Benjamin Netanyahu could still be ousted from office. We hope Netanyahu – a man who has perpetrated the most heinous war crimes – is removed from office. We hope he is made to answer for the genocide he has perpetrated.

But sadly, we have no reason to believe that this will be the end of the suffering of the Palestinian people. This is not simply a “Netanyahu problem”. Nothing offered by Israel’s opposition indicates a change of course on Palestine.

That is, unless we act. We have welcomed British Foreign Secretary Ed Miliband’s change of direction in recent weeks. But if we are to see real change in the Middle East, Britain must now make good on its promises and turn warm words into action.

Action needed now The UK’s announcement of sanctions is important. But the sanctions need to be enacted rapidly; we simply cannot wait six months. There are three priorities.

First, the foreign secretary’s sanctions package must be enacted in the broadest way possible. The core problem here is not simply about fanatical settlers. It is state policy. Israel’s government has used settler militias to carry out brutal attacks on Palestinians and their land. It is therefore the state that must face sanctions.

What is more, stopping the construction of new settlements is not enough. We must make the whole settlement economy unviable, and roll back decades of apartheid. We have ample opportunity to do so. The text of Britain’s sanctions regulations suggests the government can sanction companies that profit from the illegal settlements. We must do so. And while attention has focussed on companies bidding for the E1 settlement, we also need sanctions targeting entities that help facilitate the maintenance of the illegal settlements that already exist. This should include companies that provide finance, insurance and surveillance technologies to the settlements and the infrastructure around them.

Second, although the government has confirmed that it will stop all arms sales to Israel that materially contribute to the occupation, components for F-35 jets are still allowed to reach Israel, helping keep those planes in the air over Gaza and the West Bank. Arms licences for aircraft that help train the very forces that oversee the occupation also continue. These loopholes must be closed. Let us be frank – we should not be selling weapons to a military which is perpetrating both a genocide and apartheid.

Finally, we cannot forget Gaza. The government’s changes to the Global Human Rights sanctions regime empower it to sanction actors involved in the blocking of humanitarian aid. With Palestinians in Gaza facing disease and starvation this winter, the government must act quickly. This is not simply about individual fanatics blocking trucks; it is state policy, for which Israeli ministers must face sanctions.

And it goes far beyond emergency aid, which will simply keep Palestinians on the verge of starvation. Gaza needs to be rebuilt, and for this the siege must end. Until it does, a full package of sanctions should be applied.

An expanded and comprehensive sanctions package would be fully in line with international law. In fact, it is required of the UK. The International Court of Justice has directed that all countries must take steps to end assistance to Israel’s illegal occupation of the Palestinian territory, including ending trade and investment that assist in the maintenance of the occupation.

The impetus to take firmer, faster action is clear. Israel is trying to cut off the Palestinian people from the rest of the world. But we must use all the tools in our power to force it to change course.