By Roger Mosey Head of BBC Television News

Presenting a radio programme isn't as easy as it sounds.

Presenting Today is very difficult indeed.

You get up at a dreadful hour; you need to catch up on all the latest wire agency reports and plough through the morning's papers, sustained only by BBC coffee and cold toast; and then you have three hours on national radio, in which your merest slip automatically becomes a diary item for the following day.

MacGregor: Famed for her "on-air calm"

It's not just telling the time and remembering the name of the bloke who does Thought For The Day.

There are live interviews on subjects ranging from Afghanistan to the Brits, and the interviewees may relish the opportunity of putting in the boot if your briefing is less than impeccable.

Equally, there are the bright ideas fixed by the previous day's producers - where the guest turns out (a) to have a view diametrically the opposite of the one expected; or (b) to be unwilling to speak English; or (c) to be unable to utter a coherent sentence in any language.

In getting on for 20 years on Today, Sue MacGregor has encountered almost all the phenomena fate can throw at her.

The Today "family" is losing a key member

Through it all she has sailed on serenely - and her on-air calm has been little short of miraculous.

Behind the scenes, Today is like any other work place: there are frissons and rivalries, and mornings when colleagues would like to see each other briskly simmered in hot oil.

It is hardly a revelation that there are moments of tension between presenters and editors.

Sue would have to have iced water in her veins not to be irritated occasionally by Humphrys in testosterone-charged overdrive or Naughtie in his Worzel Gummidge mode.

Sarah Montague has filled some of MacGregor's presenting slots

She, equally, sometimes found it difficult when she moved from the single presenter splendour of Woman's Hour to the scruffier team operation on Today.

But what came out of the radio was the utmost poise and professionalism, and to millions of listeners Sue is a valued guide through the waking hours of the day.

For me as her editor for a time, the best test was always coming back from a holiday abroad and switching on the radio - and coming afresh to all her virtues.

It's a feeling which says "this is Britain, Sue's in charge and all is well".

Quality

Her achievement over the years stretches far beyond Today.

She brought Woman's Hour into the modern era, and was a reporter on The World At One in its ground-breaking era under the editorship of Andrew Boyle.

Her other roles have ranged from Conversation Piece on Radio 4 to Dateline London on BBC News 24 - and over her 35 years in broadcasting it is hard to think of any achievement by a female presenter which is greater, either in quality or in quantity.

As for the woman herself, her recently-published autobiography strips away much of the mystery of someone who was best known for her voice alone.

Happy retirement

But she is also a woman of great charm - who can be gossipy and mischievous, and an entertaining companion over a bottle of chilled plonk, as well as the refined presenter we hear on the radio.

Today will never be quite the same without her, on-air and off-air.

BBC Radio would be mad not to ensure that we still hear Sue in wider roles.

For her sake, though, it should be something which doesn't require an alarm call at 2.50am - and we should all wish her a few good nights' sleep as well as a happy retirement from Today.

Roger Mosey edited Today from 1993 to 1997.