Not one of the six strong Westminster team has worked in local government for longer than a year - but previous experience in careers as diverse as law, restaurant management and community football development at Crystal Palace FC gave them the edge over their more experienced rivals.
A delighted Rebecca West, former police sergeant and now senior cabinet support officer at Westminster, said the team
was 'over the moon' with its surprise
Lincoln City Council won the award for best strategy and Boston BC was credited with most successful partnership working.
The most impressive presentation was given by Basingstoke & Deane BC, while Vale Royal BC was judged to have fared best at the hands of the aggressive media contingent.
Feedback suggested this year's challenge was not only the biggest so far, but also the most successful.
Gordon Holdcroft, deputy chief executive of Basingstoke & Deane BC, has attended the challenge for six years. This year, he took part as an observer.
'It's the best one-day training exercise we've come across,' he said.
The top 12 teams this year
Westminster City Council, Telford and Wrekin Council's Social Climbers, Sandwell MBC, Durham CC, Brighton & Hove City Council, Vale of Glamorgan Council, Forest of Dean DC, Liverpool City Council, St Edmundsbury BC, Basingstoke & Deane BC, East Sussex CC and Boston BC.