Siân has served as a special adviser and speechwriter to the Chancellor of the Exchequer, Philip Hammond, when he was at the Department for Transport and the Ministry of Defence.
During this time, she worked on high-profile political issues including HS2, rail investment strategy, the restructuring of the Army and the Comprehensive Spending Review.
Before working in Government, she served as Mr Hammond's chief adviser in Opposition, helping to shape the Conservative approach to public spending and supporting the development of the 2010 election manifesto. This followed two years as the party's lead policy researcher on work and welfare.
Siân’s earlier career includes five years as a financial services strategy consultant and a spell as a business journalist in Cardiff. She holds a Modern Languages degree from Cambridge University.
Proudest moment? Professionally speaking, walking through the door of 10 Downing Street for the first time as a special adviser was a definite career highlight. So was - if I’m wearing my ‘other hat’ as a singer - performing as a soloist with orchestra for the first time. Personally, though, I’m most proud of my lovely son.