But the Queen had pulled out of the ceremonial welcome on a chilly Horse Guards Parade, as she continued to suffer from the side effects of a chest infection.

She told guests at the state visit that her chest infection had been a form of pneumonia, which has now cleared, but she still sometimes suffers from post-viral fatigue and bouts of extreme tiredness.

There have been criticisms over Qatar’s record on LGBT rights – and a small group of protesters shouted “Qatar’s anti-gay shame” as the royal carriages went past on the Mall.

There have been complaints about this week’s visit, including by the Peter Tatchell Foundation, which has criticised Qatar’s record on LGBT rights, women’s rights and the treatment of migrant workers.

Human Rights Watch has said the visit should not ignore Qatar’s “troubling rights record”.

In response, the UK government says it regularly discusses human rights with its Qatari counterparts and is opposed to discrimination on grounds of sexual orientation or gender.

A Foreign Office spokesman said: “Our strong, historic ties with Qatar are vital to UK prosperity, growth and security.

“The UK government is committed to continued strong relations with Qatar to deliver partnerships of mutual value.”