I'm a great fan of Zara Phillips: an Olympian who has taken her own path in life and made a success of it. She is used to winning accolades and attracting attention for all the right reasons.

Unfortunately she – and her PR team – failed terribly with a live interview she gave to Sky News last Wednesday.

She was interviewed – liberally covered in brand logos and with shiny new Range Rovers carefully placed in shot – at the Royal Windsor Horse Show where she was helping to launch a new engineering apprenticeship scheme for young women sponsored by Range Rover.

With her Grandmother serving as an engineer in the Auxiliary Territorial Service (ATS) in her youth the perfect PR story was in place.

Many journalists deride media training assuming it creates robots for interviewees who deliver a message bereft of personality. Bad trainers may well do this, but good ones allow people to become brilliant ambassadors for brands, delivering a message while making it relevant and engaging for the viewers at home.

When I'm coaching people for interviews I always make sure they are prepared for the classic "one last question". As people relax with the relief of reaching the end of the interview mistakes can be made.

On the day Sir Alex Ferguson announced his retirement and The Queen signalled she will begin to pass some responsibilities to Prince Charles, the "one last question" put to Zara Phillips was likely to be about her Grandmother.

When it was posed Zara Phillips stumbled badly, full of "yer knows", "erms", "ahs" and worried glances her answer left her looking a shadow of her normally engaging best. She was clearly ill prepped for the most basic of interview hurdles.

As someone who has chosen not to be a serving member of the Royal Family she may well wish to plough her own furrow but a question about her Grandmother was actually an opportunity to satisfy the question then steer it back onto her key message: the launch of the apprenticeship scheme.

An answer along the lines of "I don't know my Grandmother's plans but her service to this country really began when she was a young engineer in the ATS. She has talked of this time with fondness and I hope this new scheme will be an inspiration to a new generation of young women engineers".

Sadly she wasn't prepared to deliver a line like this, which makes Zara Phillips my Mis-Communicator of the Week.

Written by Edward Staite, founder of Staite Communications