Societe Generale, the French banking group, has launched a bid to combine two of the most prestigious private banking brands in the City of London by acquiring Kleinwort Benson and uniting it with SG Hambros, its UK wealth subsidiary.

Kleinwort Benson, currently part of the Belgium-based BHF Kleinwort Benson Group, is up for grabs thanks to a takeover bid for the group by the Chinese insurance giant Fosun, which is its largest shareholder.