Theresa May has defended her dealings with Saudi Arabia as she heads to Riyadh for trade talks amid widespread criticism over Britain's arms deals with the kingdom.
The Prime Minister has faced repeated calls to suspend the sales following claims of human rights abuses in Yemen under the Saudi-led coalition bombing campaign.
Labour called on Mrs May to halt arms exports to the state immediately and urged her to back an independent investigation into war crimes in the conflict.
But Mrs May shied away from attacking the kingdom's rights record and stressed how the UK's safety and prosperity are bound up in the Gulf's future.
She said: "A number of countries in the coalition have been taking action in Yemen, but in relation to the humanitarian crisis in Yemen, the UK has been a significant donor.
"Last year we were the fourth largest donor in terms of humanitarian aid, £103 million. We will be continuing to support that humanitarian issue and that's one of the issues that I'll be discussing on my trip over the next couple of days.
"The relationships that we have with the countries that I'm visiting, with Jordan and Saudi Arabia, are long term and historical relationships.
"They're important for us in terms of security, they're important for us in terms of defence, and yes in terms of trade.
"But as I said when I came to the Gulf at the end of last year, Gulf security is our security; Gulf prosperity is our prosperity."
The Saudis back the war-torn country's internationally recognised government against Iran-backed Houthi rebels.
Britain has continued to allow arms sales, with more than £3 billion of exports since the bombing began in March 2015.
At least 10,000 people have been killed during the war, according to the United Nations.
Jeremy Corbyn called on the PM to put human rights at the centre of her talks with Saudi leaders.
"Numerous human rights organisations, including the UNHRC and Amnesty International, have documented the dictatorial Saudi monarchy's shocking human rights record," he said.
"The Saudi-led coalition bombing in Yemen, backed by the British government, has left thousands dead, 21 million people in need of humanitarian assistance and three million refugees uprooted from their homes.
"Yemen urgently needs a ceasefire, a political settlement, and food aid, not more bombing.
"British-made weapons are being used in a war which has caused a humanitarian catastrophe.
"Britain must halt arms sales to Saudi Arabia immediately, throw its weight behind a ceasefire resolution at the United Nations and back a full and genuinely independent investigation of the evidence of war crimes in Yemen.
"As it stands, the British-Saudi relationship is damaging to the people of Saudi Arabia, Britain and the wider Middle East, and helping to export insecurity to the rest of the world.
"Unless the Prime Minister challenges the Saudi regime over its abuses this week, it will be clear she is ready to sacrifice human rights and security on the altar of the arms trade."
The Metropolitan Police said on Monday its war crimes unit was considering an investigation into Saudi activities in Yemen.
Andrew Smith, from the Campaign Against Arms Trade, which is trying to block UK arms sales through the courts, said: "We are always being told how much influence the UK supposedly has over Saudi Arabia.
"But it hasn't led to the regime improving human rights at home, and has only served to legitimise its brutal bombing campaign in Yemen.
"If May wants to play a positive role in turning around a dire situation, then she must end the arms sales and her Government's complicity in the destruction."