Charlotte Green and Harriet Cass, the longest-serving announcers on Radio 4, are to leave the BBC after amassing 74 years on Britain's airwaves.

Cass, 60, and Green, 56, have opted to take voluntary redundancy as part of swingeing BBC cuts that will see Radio 4 trim its announcing team from 12 to 10. They will leave the corporation in the new year.

The pair have been a fixture on Britain's airwaves since the 1970s, introducing programmes and reading news bulletins for the Today Programme through to delivering the shipping forecast.

Cass, who has referred to Radio 4 as her "spiritual home", joined the BBC in 1972, starting out on politics and editing Today in Parliament from Westminster before being promoted to become one of Radio 4's two senior announcers.

"The BBC was my first job and I thought it would be interesting for a few months," she said. "Forty years later, it's time to do other things."

Green, who won Most Attractive Female Voice on the Radio in a Radio Times poll, joined the BBC in 1978 after graduating from the University of Kent, she has specialised in newsreading since 1998.

She famously had a fit of giggles while reading a news item about the death of Hollywood screenwriter Abby Mann.

"Radio 4 listeners have always been very warm and appreciative of what I've done, whether doing the shipping forecast, reading the news or taking part in the news quiz," she said. "I'll miss the buzz of live radio, but I'm really looking forward to getting involved in new projects."

Gwyneth Williams, the controller of Radio 4, said that the pair had made an "immense contribution" to Radio 4 and would be missed.

"We will all miss them – and I know I speak for listeners, as well as colleagues," she said. "They have both chosen to move on and they go with my personal respect and affection, as well as the good wishes of everyone who has grown to know and love them over many years."

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