The Foreign Office is calling for a "full investigation" after a British man died in police custody in Dubai.
Lee Bradley Brown, 39 and from east London, died on Tuesday and Dubai police are looking into the death.
The FCO said the UK consul general spoke to police at the "highest level" but did not comment on media reports that he was assaulted by officers.
Officials have also inquired about the "safety" of four other Britons held at the same police station.
According to reports in a number of newspapers, Mr Brown, was arrested on 6 April over a row at the luxury hotel Burj Al Arab hotel while on holiday.
He is said to have been taken to a Dubai police station where he was allegedly assaulted and then left in a cell.
The Foreign Office said officials had spoken to Mr Brown's family and were providing consular assistance.
A spokesperson said: "We can confirm Lee Brown's death on 12 April while in police custody. Our thoughts are with Mr Brown's family at this very difficult time.
"The Consul General has spoken directly to the Dubai Police at the highest level on a number of times to stress the importance of a full investigation.
"The police have assured us that they are investigating and we are remaining in close touch with them."
According to the London-based Detained In Dubai support group Mr Brown's family contacted the British Embassy in Dubai with their concerns about his safety.
UK officials visited the police station where he was being held before his death but were told he did not want to meet them.
The Foreign Office added that a "number of requests" had been made on behalf of the four other Britons at the police station and UK officials visited them on 14 April and would be contacting their families.
The Embassy of the United Arab Emirates in London said the government had not yet commented on the case.
In a statement, Jumeirah Group, the owners of the Burj Al Arab hotel where Lee Brown was reportedly staying, said: "We are aware of this issue and understand it is being handled by the relevant authorities.
"We therefore have no further comment. For privacy reasons, it is our policy not to disclose any details or information about guests who stay in our hotels."