One of the 15 activists convicted of a terrorism offence for blocking the takeoff of a deportation charter flight from Stansted has spoken of her anguish before the group’s sentencing this week, saying she fears a “horrific” separation from her newborn son.

The Stansted 15, who were convicted at Chelmsford crown court in December of endangering the safety of an aerodrome, hope they will be given non-custodial sentences, though the offence carries a maximum of life imprisonment. Their convictions under the Aviation and Maritime Security Act 1990, were condemned as a “crushing blow for human rights” by Amnesty International. Their lawyers have lodged an appeal.

But Emma Hughes, a charity worker who gave birth shortly after Christmas, is deeply “scared about the uncertainty”. The best-case scenario, she has been told, will entail a home detention curfew and an electronic tag, restricting her daily movements to see her partner and their parents. “The worst case? Well, I go to prison, my partner gives up his job, my child is separated from me, I apply to enter a mother and baby unit in prison,” Hughes told the Observer. “I’m breastfeeding. Being separated from my son would be horrific.”

She added: “It’s a crazy time to be spending this already absorbing, life-changing period establishing my son in the first few weeks of his life and contemplating what will happen to us at the sentencing.”

In March 2017, the group of nine women and six men aged between 27 and 44, used lock-on devices to secure themselves to a Titan Airways Boeing 767 at the airport in Essex. It had been chartered by the Home Office to remove about 60 people to Nigeria, Ghana and Sierra Leone. Initially charged with aggravated trespass, they were later found guilty under the 1990 legislation passed in response to the 1988 Lockerbie bombing. At the time Kate Allen, the UK director of Amnesty International, likened its use in the Stansted case to “using a sledgehammer to crack a nut”.

The prosecution had argued that the protesters’ actions, which led to a temporary shutdown of Stansted, had posed a grave danger to the safety of the airport and its passengers. Other activists who interrupted commercial flights at Stansted in 2008, Heathrow in 2015 and London City airport in 2016 were charged and convicted of aggravated trespass and given non-custodial sentences.

Facebook Twitter Pinterest The Stansted 15 on the first day of their trial in Chelmsford in March 2018. Photograph: Kristian Buus/Getty Images

After almost two years of maintaining a united, supportive front, the group had been worn down by the stress, Hughes said. “We’re in contact almost every day on our WhatsApp, but some have understandably had to check out. It’s a surreal and horrific thing to endure. Being found guilty under this conviction carries such serious consequences – not just what it means for our futures, but for the rights of anyone who dares to protest.”

Hughes and her codefendants are bracing for the immediate impact on their future employment, on getting mortgages and travelling abroad. “We need to show this charge should never have been brought in the first place,” she added.

A lawyer for the group, Raj Chada, partner at Hodge, Jones and Allen, said the case was an abuse of process. “The evidence presented to the attorney general has not been disclosed and the judge has ruled against it being disclosed,” he said. “On the face of it, it doesn’t make sense. Never in a million years when the act was being introduced post-Lockerbie did anyone think it would be used against peaceful protest. Why did the attorney general sign it off?”

Stansted 15: ‘We are not terrorists, no lives were at risk. We have no regrets’ Read more

Following the group’s action, Stansted airport banned the Home Office from using its runway for deportation flights at high risk of protest activity. At least five deportation flights have since used RAF Brize Norton in Oxfordshire.

“It’s nonsensical,” Chada added, “because the 15 have been proven to be right: we know that there were some people on the flight [that they successfully stopped] that should not have been on there or legally deported. We know the Home Office isn’t fit for purpose. This has now led to 15 peaceful protesters being classified as terrorists.”