BAE Systems is the UK's biggest defence contractor and is currently embroiled in a Serious Fraud Office investigation. This concerns the alleged use of a £60m slush fund to oil the wheels of the Al Yamamah deal to sell arms to Saudi Arabia.
But perhaps the most challenging moment of Lambkin's eight months in the role occurred at the Paris Air Show in June when her boss, CEO Mike Turner, was reported as saying that BAE chairman Dick Olver 'knows nothing about our business'.
Lambkin, who is not on the board, is adamant the situation did not get beyond her control. 'Mike and Dick have a good relationship, which is quite rigorous and robust at times,' she says. 'I want two people to test each other and then come to an agreement and that is exactly what they do. Out of control is when one of them leaves.'
The sharp-elbowed impression that emerges from Lambkin's firing-on-all-cylinders exterior may partly explain her meteoric rise from a humble account executive at Lowe Bell Financial to FTSE 100 communications director in just ten years.
'I know I am confident and can be a bit punchy. But I have been humbled and the lesson I learned is that you can only lead a team if you are sensitive to your surroundings,' she says. 'If someone's got an issue I would just go and talk to them about it and that usually diffuses the situation.
I don't need to be people's best friend. I am quite happy to just work with them and socialise with my own friends.'
Those who knew her at the Chime Communications-owned Bell Pottinger Corporate & Financial (and its predecessors) remember a highly driven individual. 'When she is given something to do she always gives it 120 per cent, which does not always make her the easiest person to work with,' says former BPC&F director John Coles, now at Weber Shandwick Square Mile.
'She doesn't suffer gladly people who are not as driven as her. If there was something where all the t's were crossed and all the i's were dotted except one, she would focus on putting a dot on that i.'
Others, like Financial Dynamics MD Jonathon Brill, point out that her family and the team she works with are the important part of Lambkin's life. Lambkin links her proactive and 'blow your own trumpet' mentality with the attitude of her father, a Cambridgeshire farmer, saying she likes to extend the family ethos to BAE.
And while she admits that 'you can't win over everyone can you? You just have to crack on', BAE's 15-strong communications team has, by all accounts, received her well.
There are rumours (upon which both Lambkin and Chime deputy chairman Piers Pottinger decline to comment) that one of her first actions as director of comms was to halve the fees of her old firm, which is retained financial PR adviser to BAE.
Pottinger at any rate 'cannot speak highly enough' of Lambkin and last year recommended her to replace BAE comms chief Hugh Colver after she reneged on an agreement to join her retail bank client Standard Chartered as head of media relations.
Lambkin says she decided to leave agency life because 'I just couldn't motivate myself any more' and that her other client, BAE, trumping Standard Chartered came as a surprise.
She lists fast cars among her interests and drives a Porsche 911 - 'it's a great car by the way and it runs really well' - but running comms for the company that pressure groups and journalists love to hate should provide its fair share of thrills.
CV 1995: Account executive, Lowe Bell Financial 2002: Board director, Bell Pottinger Financial (later Bell Pottinger Corporate & Financial) 2004: Group communications director, BAE Systems.