A leading British flying school has suspended seven trainee airline pilots from Bahrain after they attended a peaceful demonstration in London against their government's violent crackdown on dissent.

The trainees' lessons at the Gatwick-based Oxford Aviation Academy (OAA) were cancelled after a request by the Bahraini authorities, who have told them to return home immediately and face questioning. Some told the Guardian they would stay in the UK, fearing arrest and torture if they went home. In Bahrain on Thursday a military court sentenced four Shia protesters to death over the killing of two policemen during anti-government protests last month.

The students' training was arranged through the Gulf Aviation Academy in Bahrain, which is ultimately controlled by the crown prince, Salman Bin Hamad al-Khalifa, whose government is accused of killing dozens of pro-democracy protesters. The order to suspend the seven came from the GAA but it gave no reason.

The trainees believe it is a direct consequence of their decision to protest outside the Bahraini embassy in London in late March and demand democratic reform of the Gulf state and an end to the killing of protesters. The trainee pilots said about 70 other Bahrainis on the course who did not attend have not been affected.

The OAA, which trains pilots for airlines including British Airways and Qantas, has come under fire for agreeing to suspend the trainees, some of whom were weeks away from qualifying and were likely to have flown for Gulf Air, Bahrain's state-owned airline.

Yasser Al-Sayegh, founder of Bahrain Peace and Justice, based in Manchester, accused the company of placing the value of long-term contracts with Bahrain above the pilots' welfare and said they appeared to be endorsing the Bahrain government's attempts to suppress protest.

"The school should be much harder with the government of Bahrain," he said. "They should be questioning why the pilots should be suspended. They are putting business before human rights and that is not British values."

The OAA said its contract to train the pilots was with the GAA rather than the students and that it suspended them because it was directed to do so by GAA. It added it would restart training if instructed to do so. It declined to respond to criticism.

"My main worry is that I will be detained at the airport," said Jalil, one of the trainees who is using a pseudonym to protect his family in Bahrain. "If we are tortured inside the prison we would fail our airline medical, which would ruin our chances of being a pilot."

"We have been hearing similar stories of fellow Bahraini students in the UK and around the world who were punished by having their scholarships revoked for their bravery to raise their voices and speak their beliefs, claiming that they offend the image of the kingdom of Bahrain," the students said in a statement.

The problems for the pilots began on 14 April when Khalid Khalaf, an official at the GAA emailed Philip Edwards, the OAA manager, requesting him to ask seven named students "to book their tickets and come back to Bahrain immediately".

Mahmood al-Balooshi, chief operation officer of the GAA, then emailed the pilots last week stating: "You are requested to attend a compulsory and obligatory meeting at Gulf Aviation Academy premises at 10am on Monday 25 April 2011. Failing to attend the meeting will result in the immediate termination of your contract."

The pilots said they were paying their £80,000-per-person fees through loans taken out from a state bank and their inability to complete the course and qualify left their finances in a perilous state.

On Thursday the government denied opposition claims that hundreds of public employees have been dismissed on the grounds that they took part in protests. According to the Middle East Studies Association, 111 civil servants were summarily fired from the ministry of education on 17 April. The Bahrain Centre for Human Rights estimates 31 people have been killed in the crackdown on dissent and more than 800 people detained.

At least nine Bahraini students at universities across Britain have already been ordered home by the government and had their scholarships cancelled after they attended an anti-regime protest outside the BBC headquarters in Manchester. Their families were pressurised to bring them home and the students involved told of "strong and well-founded" fears that they and their families could suffer beatings and torture as a result of the Bahrain government's crackdown on the protest 3,000 miles away.

The country has since told the students if they want to challenge the decision they can do so in court in Bahrain.

"The students were advised to follow up the matter with the ministry directly or through our office and appeal their case if need be," the cultural attache in London said. "Since then, no student made any effort to contact the ministry of education or our office. Moreover, they have the right to appeal at Bahraini court if they felt injustice by the decision.

"Students have the right to continue their studies as their tuition fees are paid in full this year and no one asked them to leave their study and head back home, it is their own choice to take. Their families were contacted to be informed solely about the decision as they are co-signers in the agreement."

The students dispute this and say their families have been put under pressure to bring their children home and are fearful for their safety if they do not, some calling them in tears telling them to return. Some said their subsistence grants had been stopped, which means they can no longer pay their rent.