Saudi Arabia: how did the U.K agree to sign weapon deals with it?

[WinterHold]

The crown prince of Saudi Arabia visited the U.K, and ironically he received the welcoming of a King, with lots of arm deals being signed to arm the the Saudi army:

'A national disgrace': fury over £100m aid deal between UK and Saudi Arabia

https://www.theguardian.com/global-devel...udi-arabia

Saudi Arabia moving towards purchase of 48 Typhoon fighter jets from UK after Crown Prince visit

The deal potentially worth some £10bn to BAE Systems will prove controversial due to Saudi's involvement in the Yemen conflict

http://www.independent.co.uk/news/uk/pol...47971.html

in total neglecting of human rights organization reports about the crimes the kingdom is carrying on in Yemen:

https://www.amnesty.org/en/press-release...-children/

https://www.hrw.org/world-report/2017/co...ters/yemen

Despite the reports about the massacres the Saudi airstrikes are causing; the U.K is still providing the kingdom with fighter jets and ammunition to strike even more heavily. Still; there's a voice inside Britain that stands against the kingdom's brutal regime; and thanks are not enough to pay them gratitude.

Moreover; the government of Theresa May is leading the UK in the same terrible foreign policy that kept being repeated since WW1; supporting dictators like the Sauds is one of the terrible things about that policy.

https://en.wikipedia.org/wiki/Yemeni_Civ...93present)

As the years pass by; civilian casualties pile up in Yemen; the dead civilians are exceeding the 5000+ .
The number is probably bigger than that.

The Houthis have long been accused of being proxies for Iran, since they both follow Shia Islam (although the Iranians are Twelve-Imam Shias and the Houthis are Five-Imam Shias). The United States and Saudi Arabia have alleged that the Houthis receive weapons and training from Iran.[120] The Houthis and Iranian government have denied any affiliation.[121] The African nation of Eritrea has also been accused of funneling Iranian material to the Houthis,[122] as well as offering medical care for injured Houthi fighters.[123] The Eritrean government has called the allegations "groundless" and said after the outbreak of open hostilities that it views the Yemeni crisis "as an internal matter".[122]

Sectarian religious aspects also show their signs in this war; the Arabic alliance -led by Saudi Arabia- is Sunni; their foes in Yemen are Shiite.
Saudi Arabia did play a huge role in making this sectarian war flame up through the years, even before invading Yemen.

How come, after all this, the British current regime agrees to arm Saudi Arabia