Exclusive: Families of people detained overseas fear diplomats are pushing back against foreign secretary’s plans

Families of prominent British prisoners detained abroad have urged the foreign secretary to deliver on pledges to help secure their release amid signs of growing resistance from diplomats.

David Lammy, the foreign secretary, vowed in opposition to appoint a special envoy to help secure the freedom of those detained for years without a fair trial. Giving British citizens a legal right to consular access when they run into trouble overseas was also a Labour manifesto pledge.