In the letter sent to Lammy on Tuesday, lawyers for Qesser Zuhrah, Amy Gardiner-Gibson, Jon Cink, Heba Muraisi, Teuta Hoxha and Kamran Ahmed say they have all been refusing food since early November.
Ms Zuhrah and Ms Gardiner-Gibson have been refusing to eat for 38 days as of Wednesday, according to supporters. Each of the others are said to have been refusing to eat for at least 30 days.
Two further detainees awaiting trial in Palestine Action-related cases began refusing food in the last fortnight.
“Each of our clients’ health is deteriorating rapidly,” says the letter.
“Five of our clients have already been hospitalised during their strike.”
The protest began over a series of demands including a call for the ban on Palestine Action to be lifted and for a defence firm with links to Israel to be shut down.
Three High Court judges are expected to rule within weeks on the lawfulness of the ban. That review is a result of the courts granting the group’s co-founder permission to challenge the home secretary’s decision.
The protesters say they have been denied bail, which they want, or a fair trial – although they have faced the same legal process as other defendants in Crown Court trials – hearings that have been independently witnessed by journalists.
In the letter to Lammy, the group’s lawyers say they are considering legal action over human rights breaches.
“We, as their legal team, are under no illusion that their commitment to their cause, and their will to ensure that their demands are met, is iron-clad,” the letter says.
“We are concerned that, should this situation be allowed to continue without resolution, there is the real and increasingly likely potential that young British citizens will die in prison, having never even been convicted of an offence.
“We therefore request an urgent meeting with you, in an attempt to resolve this situation, before it becomes too late to avoid the death of one or more of our clients.”