Ayman Najafi has 30 days in which to appeal against his sentence
A British man and woman jailed in Dubai for kissing in public have lost their appeal against their conviction.
Ayman Najafi, 24, and Charlotte Adams, 25, were sentenced to a month in prison with subsequent deportation and fined about £200 for drinking alcohol.
The pair were arrested in November after a local woman accused them of breaking the country's decency laws by kissing on the mouth in a restaurant.
Najafi said he was "very disappointed". The pair plan to make a second appeal.
The initial complaint against them was made by a 38-year-old woman who said she was offended by their behaviour at the Jumeirah Beach Residence, where she was dining with her daughter.
The pair's defence lawyers said the woman - who did not appear in court - had not seen the kiss herself, but had been told by her two-year-old child that the girl had seen them kissing.
Magdi Abdelhadi, BBC News
Dubai looks very Western with its gleaming apartment blocks and super modern shopping malls. The Western façade can, however, lull the unsuspecting visitor into believing that it is also a liberal society.
And that appears to be primarily why Western visitors have recently fallen foul of the law there.
Scratch the modern surface and you discover a conservative Muslim culture, arguably far more so than many others in the Middle East.
Consumption of alcohol is restricted to a small number of places, mainly for Western visitors and expatriates.
Although there is no strict separation of the sexes as in neighbouring Saudi Arabia, the boundaries for what you can and cannot do in public can be tricky, especially for outsiders. While an unmarried Western couple can share a room in a hotel - or even live together - they are expected to observe local custom when outside their home.
So sentencing a couple for having kissed in public may be shocking for Western public opinion, but will most likely be applauded in conservative Arab societies, especially where there is a perception that Westerners are often expected to be given a preferential treatment.
The defendants also claimed they had merely kissed each other on the cheek, and therefore had not broken any laws.
The BBC's Ben Thompson, at the court, said the judge spoke entirely in Arabic as he quickly dismissed the appeal, saying he upheld the previous sentence.
They were fined 1,000 dirhams, which is about £200. They now have 30 days to appeal.
It was left to the defence lawyer to explain the verdict to Najafi and Adams.
Najafi said after the case: "It's very harsh, based on contradictory evidence. The courts haven't called on any of our witnesses who are prepared to testify that this didn't happen."
His mother, Maida Najafi, told the BBC her son had grown up in the UK and was used to common British greetings.
"Maybe they think he should know better because he's from a Muslim family but Ayman grew up in this country, and that's the normal greeting... in this country," she said.
The pair decided not to start their sentence immediately, but the Dubai authorities are holding their passports so they are unable to return to Britain.
Professor John Strawson, an expert in Islamic law, told BBC Radio 5 Live he was not surprised by the judge's decision.
He said: "The problem in this particular case is that one of the British citizens is of Muslim origin.
"And I think that the combination of the alleged kissing and the consumption of alcohol in an illegal place, meant that this was a case that the authorities really wanted to pursue, and they are probably sticking to their rigid interpretation of the law."
Professor Strawson said the Dubai authorities often turned a blind eye to foreigners' behaviour, because of the high income that comes from tourists.
But he said Dubai had recently issued new explanations tightening up their laws.
The Foreign Office advises Britons going to Dubai, which is part of the United Arab Emirates, to be wary of breaching local customs.
A statement on its travel advice website reads: "Britons can find themselves facing charges relating to cultural differences, such as using bad language, rude gestures or public displays of affection."
Najafi, from north London, had been working for marketing firm Hay Group in Dubai for about 18 months.
The case is the latest in a series of incidents over recent years in which foreigners have broken Dubai's strict decency laws.
In March, an Indian couple in their 40s were sentenced to three months in jail in Dubai after sending each other sexually explicit text messages.
In 2008, two Britons accused of having sex on a beach in Dubai were sentenced to three months in jail, though the sentences were later suspended.
To hear more of the interview with Maida Najafi tune in to John Pienaar on BBC Radio 5 live's Weekend News at 2100 BST on Sunday.