TONIGHT: Preview of Dispatches and Horizon

Dispatches (9pm C4) Andrew Marr, editor of this newspaper, followed the 1992 general election as political editor of the Economist. His insider's account of the media campaign, which has since been updated, was first broadcast on polling night in 1992, and revealed the symbiotic relationship between the parties, their spin doctors and political journalists. Hindsight of John Major's surprise, against-the-pollsters victory adds a tasty crust of historical irony to his interesting chronicle of an election result unforetold (122970).

Horizon (9.30pm BBC2) How a group of deaf children born in pre-revolutionary Nicaragua (where they were kept hidden and given no education) developed their own complex sign language and thus provided linguists with an answer to that old conundrum - is language learned, or is it innate? (780135)