On the day, Biggar was told by wife Bridget to wear a dinner jacket in the evening, leaving him thinking the opera, or perhaps the ballet, was in store.
Little did he know though that around 80 guests - including Lib Dem Lords Newby and Reynard and a 25-piece orchestra - were lying in wait at Whitehall's National Liberal Club, to which he was lured by staff.
Following a shocked reaction, the orchestra played some of his favourite tunes including music from Steve McQueen film The Thomas Crown Affair and Carmina Burana.
Biggar said: 'It really was a surprise. I was told to have a dinner jacket with me and my wife is musical so I though it might involve that, but I had no idea what was planned.'