Sibling loyalty: Nigella bites back at 'Telegraph'

Although representatives for Ms Lawson were at pains to stress yesterday that a "personal commitment" had led to her withdrawal, almost everyone else assumed it was because her brother Dominic Lawson stepped down last week as editor of The Sunday Telegraph, without advance warning and after 10 years at the helm.

Ms Lawson has already showed her backing to her older brother by turning up to prepare the smoked salmon bagels, served alongside the champagne, at the "farewell party" thrown by Lawson and his wife, Rosa Monckton, at their Chelsea home after his abrupt dismissal.

On 2 July, Ms Lawson was due to put in a two- hour "In Conversation" appearance on the newspaper's stand at The Daily Telegraph Home and Garden Fair at Olympia in west London. However, a spokeswoman for Ms Lawson has confirmed she will not now be attending. She said: "Nigella has had pull out due to a personal commitment,'' which, she stressed "has nothing to do with her brother's sacking".

A spokesman for the show's organisers, Clarion Events, said they could confirm she had cancelled her appearance but had no further comment. As well as a number of leading garden and interior designers, the show also includes appearances involving several Telegraph writers and columnists as well as other cooks and food writers.

Ms Lawson, 45, and her brother, 48, come from a close knit and well-connected family. Their father is Lord Lawson of Blaby, Chancellor of the Exchequer for many years under Margaret Thatcher.

The family has strong ties with the Telegraph Group. Like her father and brother, Ms Lawson began her career as a journalist and was once restaurant critic for The Spectator, which the Telegraph group owns and which both her father and brother also edited at different times.

Mr Lawson's departure from The Sunday Telegraph is believed to have been due to a combination of a desire for a fresher appearance to attract new readers, although there has been speculation it was also due to his own sacking of Con Coughlin, the newspaper's managing editor, who was close to the Telegraph Group's new chief executive, Murdoch MacLennan.

Ms Lawson's spokes-women declined to say exactly what she would now be doing on the day, saying: "Since it is personal, we will not be disclosing what that commitment is.'' However, it is quite possible Ms Lawson may also have found the attractions of two competing events – the final of the NatWest Cricket series at Lord's or the Live8 concerts in Hyde Park – preferable to an audience of Daily Telegraph readers.