A trial found that introducing airport-style checks would be impractical and antagonise the public.Link
The transport minister, Tom Harris, said the public would not accept the resulting delays and there would be objections about personal privacy if an extensive screening regime was introduced.
"Screening equipment and dogs can be effective in the railway environment," said Harris in a written statement to parliament. "However, given the very large passenger flows and thousands of entry points on the UK rail and underground networks, 100% airport-style screening is currently not feasible."
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.