The president of the United Arab Emirates is on a two-day state visit to Britain amid claims that three Britons were tortured in Dubai before being jailed on drug charges.
Sheikh Khalifa Al-Nahyan will be hosted by the Queen at Windsor Castle. He will meet David Cameron on Wednesday.
Mr Cameron has said he will raise the case of the imprisoned Britons, who were jailed for four years each.
The UAE is Britain's largest export market in the Middle East.
The two countries have a growing partnership in defence and security.
President Al-Nahyan's state visit follows one made by the Queen and the Duke of Edinburgh to the UAE in 2010 and a visit there by Mr Cameron last November.
The president's late father, Sheikh Zayed bin Sultan Al Nahyan paid a state visit to the United Kingdom in 1989.
Annual bilateral trade between the UK and the UAE now exceeds £10bn. More than a million Britons visit the UAE each year.
A squadron of RAF Tornado jets is based at Al-Minhad, a discreet and well-guarded airbase south of Dubai, which is one of the seven emirates which make up the UAE.
The BBC's security correspondent, Frank Gardner, says millions of pounds have been spent by the UAE upgrading the base, which will soon serve as a vital staging post for the withdrawal of British combat forces and their equipment from Afghanistan.
Torture claims
On Monday, east Londoners Suneet Jeerh, 25, Grant Cameron, 25, and Karl Williams, 26, were found guilty of possessing synthetic cannabis in Dubai.
The men say they were subjected to torture by police, including electric shocks and beatings.
Police in Dubai have denied any wrongdoing and say an internal investigation into the torture allegations found no evidence to support the claims.
Legal rights charity Reprieve has taken on their case and, in an earlier letter to the campaign group, the prime minister wrote: "We continue to press for evidence for a full, impartial and independent investigation into the allegations.
"The absence of an independent medical examination remains a concern.
"During the state visit of His Highness Sheikh Khalifa bin Zayed there will be opportunities to raise a wide range of issues including concerns about this and other consular cases."
