The 25-year-old man came to the UK from Afghanistan as a refugee in 2010 and was granted citizenship in 2015.
He returned to his country of birth in July to get married after completing his third-year exams.
The student, who did not want to be named, told the PA news agency: “At that time there was no talks about the Afghan government collapsing and I got married two weeks ago.”
”Just a week after I got married I heard on the news that the Afghan president had run away and the Taliban were coming, since then I’ve been fearing for my life and for my wife’s life because she is not a British citizen, she is just Afghan.
“I feel like the British Government has left me and my loved ones at the mercy of the Taliban.”
The newly-wed spoke to PA as he tried to reach the airport for a fourth time, with gunshots frequently audible in the background.
“We are making our way to the airport but we know when we get there, there will be a huge crowd and most of them don’t have any passports,” he said.
“We tried twice last night but we couldn’t even reach the gate of the airport so we had to go back – we stayed near the gates for 10 hours but we couldn’t get to the international forces to tell them I’m a British citizen.”
He said he and his wife were trying again to “see if we get lucky”, but added: “There are gunshots near the airport and people are trying to flee.”
“It’s very scary at the moment,” he said.
The couple contacted the British embassy seven days ago, but have received no guarantee they will be evacuated, or even a phone call from an embassy official.
The pair have been hiding in the home of a family friend in between their attempts to get to the airport.
“We try to keep our morale up and we tell ourselves we are safe there, because if I show that I am upset, then my wife will be anxious.”
The young man said the Taliban had been looking for foreign citizens in some parts of Kabul, but in other parts the situation was calmer.
“People have been killed near the airport trying to flee but I am not following the news because it increases my own anxiety,” he said.
Once (the Taliban) are unveiled and they show their true faces we know what kind of people they are - they have no mercy on children, on women, on any foreigners, on no one.
British student trapped in Kabul
He fears he will be an easy target for the Taliban, saying: “Everyone can spot that I’m a foreigner … shopkeepers, barbers, everyone.”
After passing a Taliban checkpoint, he told PA: “It was quite scary. I’m getting palpitations, I don’t know why the British Government has abandoned us.
“They were saying on the news ‘we are evacuating our nationals’ but I don’t see any sign of that.
“They haven’t called me and it has been seven days, I feel like they have left me and my wife at the mercy of the Taliban.”
Asked if he believed the Taliban may be a reformed group compared to the Government of the 1990s, he said: “I think if the Taliban are hiding their true face.
“Once they are unveiled and they show their true faces we know what kind of people they are – they have no mercy on children, on women, on any foreigners, on no-one.”
He continued: “At the moment it’s hard to describe my feelings, I am trying to find words – I am utterly shattered, upset, anxious and feeling helpless and hopeless at the same time.”
When asked what would happen if he ended up trapped in Afghanistan, he replied: “That will be the end of my life, the end of my dreams.”