Rhodri Marsden's interesting objects: The presenter's telephone

* Fifty years ago this weekend, the launch of the new BBC2 channel was wrecked by a London power cut. Scheduled programming was replaced by live footage of an embattled journalist, Gerald Priestland (pictured above), sitting at a desk at the BBC's former HQ in Alexandra Palace and reading a hastily-prepared news bulletin. As the chaos unfolded, the phone on his desk rang. "Excuse me," he said. "Yes... I can. Mm-hm. Right you are. Goodbye!"

* Gerald had put paid to the notion that the presenter's telephone was merely a prop; in a pre-earpiece era, it gave the presenter crucial access to the producer in moments of crisis. Viewers love things going wrong, of course, and tapes of such crises are cherished. Perhaps the most famous is David Dimbleby's conversation during a gremlin-affected 1976 edition of Panorama. "What am I supposed to tell the Panorama audience?" he asked, before announcing to viewers that he'd "sit in silence" while the mess was sorted out.

* Other highlights include Archie Macpherson picking up the receiver during a 1980 edition of Sportscene to be met with audible and ferocious cursing from the producer, and Tyne Tees continuity announcer Colin Weston receiving a panicked call to tell him that his microphone wasn't switched on. Michael Aspel recounts a story of his phone ringing while reading the news, failing to answer it in time and murmuring, "I've told you not to ring me at work, dear" into the receiver.

* Some of these phones were indeed props – rumour has it that John Craven's snazzy Newsround phone had one metre of cable with no plug – but the emergency phone still lurks. In September 2010, on the first edition of ITV breakfast show, Daybreak, Adrian Chiles revealed an old model lurking under the sofa labelled 'Lift handset to call producer'. He did. The producer reassured him that everything was fine.

@rhodri