The UK sells more arms to Saudi Arabia than to any other country and wants to sell even more. David Cameron visited the country in November to push Eurofighter sales for arms company BAE Systems, but failed to agree a deal. Now BAE is trying to finalise a deal ahead of the publication of its latest results this week. The BAE share price is expected to fall if sales are not confirmed.

Andrew Smith, spokesperson for CAAT said: “It is clear that the UK is already pulling out all stops to try to negotiate a deal on behalf of BAE. Is it possible they have gone one step further by sending Prince Charles to do their bidding? He must disassociate himself from BAE's ongoing sales drive and end his damaging and dangerous relationship with this repressive and despotic regime.”

There are few countries where human rights mean as little as in Saudi Arabia, with severe constraints on freedom of speech and liberty from a government that has been widely condemned by human rights organisations.

Andrew continued: “We are calling on the Prince Charles and UK government to use their international influence to draw attention to the human rights abuses taking place in Saudi Arabia, rather than giving them legitimacy.”

Prince Charles has made nine previous official visits to the country. In the most recent Economist Intelligence Unit Democracy Index it was ranked 163 out of 167 countries and was given zero points for “electoral process and pluralism”. The only countries ranked lower were Syria, Chad, Guinea Bissau and North Korea.

Over the past five years the UK has licensed over £5.6 billion worth of weaponry to Saudi Arabia.