Gerard Lyons, the former economic guru at Standard Chartered bank, has re-emerged as the chief economic adviser to the Mayor of London.
It is the first time that Boris Johnson has had a full-time paid economic adviser. Previously he took counsel from an informal group of economists which included Roger Bootle and Mr Lyons.
Mr Johnson approached Mr Lyons shortly after he was re-elected in May, and had little difficulty convincing him to take the role.
Mr Lyons, who left the bank two weeks ago, said: "After 13 long and happy years at Standard Chartered, I was honoured and delighted to be offered this new role by the Mayor. I am looking forward to working with him to ensure the continued success of London as a major international city. We need to place London at the centre of the shift in economic balance and power in the world."
Mr Johnson said: "Gerard has decades of experience analysing the economic outlook at all levels and is renowned for his forecasting to major institutions in the City and on the international stage. It is increasingly evident that if London's businesses are to stay ahead of the game and compete in the global market, we need the best strategies and policies informed by the very best overarching economic advice. I believe that Gerard will bring that expertise to my excellent team at City Hall."
While Mr Lyons, 51, said he saw his new job as "non-political", friends said he would have little difficulty working alongside Mr Johnson. He is certain to have taken a significant pay cut with his new salary of £127,200, and will work for 29.6 hours a week.
"The mayor offered me a clean break from the City," Mr Lyons said. "Part of my job will be defining and protecting London's roles within the European Union. It will also be about reinforcing the fact that London is about much more than just the City – it has great technology, services, retail and even pockets of industry."