The dazzlingly handsome, cocktail-drinking, spinach mousse-eating James Lundie

It has never been possible for anyone to talk about James Lundie without mentioning his appearance. He is traditionally, universally rated as the Most Handsome Liberal Democrat – not a wide field, but still an achievement – and one veteran female journalist once referred to him as "dazzlingly handsome, nay, gorgeous". The journalist Lynn Barber did at least add, enigmatically, that Mr Lundie was also "very knowledgeable about sharks".

However, in a career that has spanned 14 years split perfectly between politics and political lobbying, Mr Lundie – Jamie to his friends, "Junders" to followers of his Twitter output – has demonstrated repeatedly that he is far more than a pretty face. He began his parliamentary career in 1996, as an adviser and speechwriter for Paddy Ashdown during his final three years as leader of the Lib Dems, where he first met the then leader's ferociously intelligent policy director, David Laws.

Mr Lundie survived the shake-up when Lord Ashdown moved up to the House of Lords, remaining in the leader's office, firstly as a senior researcher to Charles Kennedy and then, after 2001, becoming his deputy press secretary. Mr Laws entered Parliament in 2001, after inheriting Lord Ashdown's Yeovil seat, and subsequently moved into Mr Lundie's home in Kennington.

Two years later, Mr Lundie left the Lib Dems' parliamentary operation after being offered a job with lobbyists Edelman Public Affairs. He has since risen to the position of director, overseeing accounts in areas including financial services, transport and charities. It is clearly tough work, as revealed by a guilty tweet from Junders on 5 November last year: "How many chocolate bars constitutes too many when you're pulling a late one at the office? Four is OK right?"

His Twitter feed, which amounts to nine tweets ending with the news that Junders was falling in love with cheese again, on 19 March, reveals something of a social life that Mr Laws says they do not share. Mr Lundie, for example, confesses to a love for the trendy restaurant Andrew Edmunds, in Soho, and reveals that he "spent the night drinking French 75 [cocktails] and eating spinach mousse with lovely friends. Yummy".

But Mr Laws and Mr Lundie clearly share a political obsession. Before the election, while Mr Laws was spearheading his party's push for a share in Government, his partner was writing a commentary on the Lib Dem campaign for the Edelman website. It was remarkably prescient.

"The Liberal Democrats genuinely want this coalition to work," Mr Lundie wrote last week, "both because it allows them to introduce policies in which they believe but also because it shows the British people that co-operative politics cannot only be made to work, but actually to flourish." If it flourishes, it may now have to do so without one of its most able members.