It added: “Under this approach, every sector will be required to implement a workforce strategy focused on training British workers, or risk losing access to the immigration system, as part of wider efforts to reinforce the integrity of the points-based system and end dependence on lower-skilled international recruitment.”
TfL is obliged to comply with the changes, which took effect on 22 July and will remain until at least the end of 2026.
It is believed many of the workers took jobs on two-year graduate visa schemes thinking they could later move into skilled worker positions, according to the RMT union.
The transport body currently pays a £31,000 starting salary for graduates and advises candidates who need sponsorship to see if they can get this before applying.
Trainee station staff are believed to earn between £35,300 and £41,800, the latter of which is only £100 above the new £41,700 per year minimum salary threshold.
RMT general secretary, Eddie Dempsey, said: “Our members took these jobs in good faith, on the understanding that they could progress and continue building their futures here.
“Now the new government rules risk shattering these workers’ lives and leaving gaps in employment for London Underground.”