right - is discussing samcam's outfit justified? yes i think it is. as has been said before, we can discuss politics in the appropriate threads, but this is S&B and we do tend to comment on people in the public eye - why should samcam be exempt?
also i would say this, for a person to get to the top of their profession, their partner needs to be behind them 100%. i doubt samcam has really been dragged into number 10 kicking and screaming and she would have been well aware of the scrutiny she would be under (a la cherie). i'm sure it is vile to be living through it, but she knew that was part of the deal.
furthermore, we do need to consider her history and role. whether it has been the royal family or politicians/their partners, there is a track record of people in the public eye wearing british designers to promote british fashion - particularly on trips abroad. but the difference with samcam is precisely that she is NOT just another powerful man's wifely clotheshorse.
fashion is one of our leading creative industries. she herself worked in the industry, and would know how people are styled, what works and so on. she would also know that as a designer you want your item - dress/handbag (in her own case)/shoes/whatever - to be shown at its absolute best to get people thinking, i like that, i'll check out that designer - which ultimately translates into sales that are beneficial for UK plc.
to her credit she makes a conscious choice of wearing (mostly) british fashion, but in this case if she had (as others have said) just put her hair up to show off the neckline, she would probably have done herself and the designer a huge favour. so, my comments come from expectations based upon her previous career - as a woman in her own right - and make no judgement on her personally, her character, her husband or her politics. just because her style mojo is slightly off does not mean she is lacking in some way! gawd forbid.
after all, she wouldn't be the first 40-ish working mother to be having a wardrobe/presentation/posture crisis