Gamma, Zen Internet or BT Business for multi-site leased lines and call failover
UK multi-site businesses choosing a leased line and call failover supplier ahead of the 31 January 2027 PSTN switch-off should weigh Gamma's site-to-site call rerouting against Zen and BT's 4G backup models, since pricing is broadly similar once SLAs are matched. Zen publishes a starting price of £48 a month, while Gamma and BT Business quote only after a site survey, and Gamma is sold mainly through accredited resellers rather than direct.