Why did the PM's wife need an aide?

Isabel Spearman (r), here at a London Fashion Week show with Samantha Cameron in 2011, was reportedly an influential member of Downing Street staff

Among the names on a leaked list claiming to be former PM David Cameron's resignation honours is his wife's special adviser Isabel Spearman - widely described in newspaper reports as her stylist.

Why would the prime minister's spouse need her own staff?

When Isabel Spearman was appointed special advisor to the prime minister's wife in 2010, on a reported salary of £60,000 - covered largely by taxpayers' money - it raised some eyebrows.

Known to friends and acquaintances as "Bells", the former PR executive was a trusted and well-connected choice, having previously worked for both Mrs Cameron's mother and a close friend.

Her role, reports claimed, was to curate Mrs Cameron's wardrobe and image - but a more accurate job title may have been executive assistant or even "chief of staff".

Profiles paint her as a shrewd, organised and influential member of Downing Street staff; a personal confidante to Mrs Cameron, responsible for everything from running her busy diary to handling correspondence, to organising official events - her "Girl Friday", as the Evening Standard put it.

It is a role that "absolutely matters", says brand psychologist Jonathan Gabay.

"If we look over the pond at US presidential elections, we see that the spouse is clearly a very powerful figure. People are fascinated by what makes political leaders tick, and the partner is key to that.

"Managing and branding them well is essential for today's political market.

"It didn't come across at any point that she was trying to steal the limelight. She had to be appropriate to the message her husband was trying to get across."

Mrs Cameron with her husband outside No 10 following the 2015 general election

Isabel Spearman at a Tatler magazine party in 2011

Mrs Cameron is not alone in having her own staff paid for by the public purse. Sarah Brown had three employees.

According to the Guardian, Michelle Obama has a team of no less than 24 - although the office of First Lady is viewed as a much more significant role than that of the UK prime minister's wife.

Author and commentator Sonia Purnell, who looked closely at British PM's spouses when writing First Lady, a biography of Churchill's wife Clementine, says many have found navigating the role a difficult task.

Harold Wilson's wife Mary, for example, was initially so overawed at being the prime minister's wife that she would be physically sick every morning.

'Meek and retiring'

During her time at No 10, Mrs Cameron hosted regular receptions for volunteers, patronised several charities, and was also an ambassador for the British Fashion Council.

But Ms Purnell feels Samantha Cameron's interpretation of the role has still been far too hands off.

"There is no job description. Cherie Blair said as much. But I would say it's a disappointment when spouses don't do anything with it. You do have a platform, and it's beholden on you to do something with that."

She argues that Mrs Cameron's public persona came across as "meek and retiring" compared with someone like Michelle Obama, who has carved out her own issues to campaign on.

Samantha Cameron and Michelle Obama have arguably taken different approaches to being the spouse of a leader

Style commentator Professor Sarah Niblock, from the University of Westminster, agrees that while Mrs Cameron's public image has been carefully managed - "dignified, prudent, and often in Tory blue" - she has failed to convey authenticity or personality.

"A stylist should help someone project who they are. Their values and qualities. The problem is that we haven't really heard anything of Samantha Cameron. We don't know what she's like..."

It is fair to say that Samantha Cameron has not generally given interviews or made speeches. It is also true, however, that she has largely avoided public faux pas, despite having been in the public eye for more than six years.

Samantha Cameron wore a Marks and Spencer's dress when she accompanied her husband to the 2009 Conservative conference

She received criticism from some quarters in 2011 for not wearing a hat to the Royal Wedding, and again in June for wearing a sleeveless dress to the Queen's 90th birthday service at St Paul's Cathedral, but has otherwise survived the intense scrutiny of the media relatively unscathed.

And Prof Niblock acknowledges that Mrs Cameron was seen to promote British designers and often wore high street brands. But she argues it was not enough to warrant awarding her assistant with a gong.

"I cannot see how she has added anything to the British zeitgeist or furthering women and British life.

"But we don't know what the brief was. If the brief was for Samantha Cameron to just sit there on her husband's arm and not rock the boat, particularly after Cherie Blair perhaps, maybe she has earned her award."

Mrs Cameron's choice of a sleeveless dress for a service celebrating the Queen's 90th birthday was questioned by some

She also faced criticism from some newspapers for not wearing a hat to the Royal Wedding in 2011

All Mr Cameron's nominations for honours will be reviewed by an independent board, but his supporters say all of those on his list deserve recognition.

"These people will have worked under intense pressure in No 10, where everything is required yesterday, immediately," Conservative MP Sir Desmond Swayne told the BBC.

"You don't take holidays, you don't leave at the end of the day. It's an extraordinary environment and atmosphere."

'Difficult line'

And the ex-prime minister is not alone in having rewarded Downing Street staffers in a resignation honours list, journalist Andrew Gimson, a contributing editor for Conservative Home, points out.

In 1997, Sir John Major rewarded a number of former staff, while in 1990 Margaret Thatcher recognised staff including her personal physician and her cleaner.

As for Mrs Cameron, Mr Gimson argues she and her staff managed to maintain a professional and self-possessed appearance at all times, and credits her with being a shrewd business woman - with a healthy desire to keep out of politics.

"She looked elegant, she never embarrassed and we never knew what she thought about anything. Most of us by a special effort could carry that off for a day or two. But it can become very tiresome. And one lapse and you can be all over the Daily Mail.

"She managed to tread an incredibly difficult line. I admire that."