THE head of Radio Solent has left her post – but she will be back, say BBC chiefs.

Mia Costello’s departure comes after listener figures revealed the BBC station had lost nearly a fifth of its audience in just a year.

The corporation last night said Solent’s station manager has only left on a temporary placement elsewhere within the organisation – to teach editorial leadership – and would be back within a year.

The plummeting listener numbers follow a number of controversial moves at the station, including culling popular presenters and banning “elderly voices”

from the airwaves.

Names including Richard Cartridge, Peter White, Dennis Skillicorn, Chris Walker and Pippa Greenwood all disappeared from the Southampton-based station as it attempted to appeal to younger listeners.

The shake-up upset many Solent followers, but that dismay turned to anger when an internal memo from Ms Costello to staff was leaked to the Daily Echo. In it, she urged workers not to allow anyone sounding over 65 to be put on the air.

“Only put on callers sounding in the 45- 64 age range. I don’t want to hear really elderly voices,” read the memo.

Ms Costello had to go on air to issue an apology after widespread criticism.

The latest listener figures from radio analysts RAJAR show Radio Solent lost 58,000 listeners – almost 20 per cent of its audience – in just a year.

That made it one of the biggest losers among BBC local radio stations, with listener figures falling to 236,000 in the last quarter of 2008, from 294,000 in the same period 12 months earlier.

And the amount of time people spent listening to the station plummeted by more than a quarter, with the total hours people were tuned in dropping from 3,503,000 in December 2007 to 2,567,000 in December 2008.

That also meant Solent’s audience share was slashed by 25 per cent – down from 11 per cent to 8.2 per cent.

A BBC spokeswoman last night confirmed Ms Costello has left her role, but said it had nothing to do with listener figures.

She said Ms Costello has successfully applied to go on a temporary placement, of between six and 12 months, elsewhere in the corporation.

The spokeswoman said: “All BBC staff, especially senior management, are encouraged to explore other spheres of our work through placements.

“Mia is taking a break from station management having won an attachment at the BBC’s College of Journalism in London, teaching editorial leadership.”