Christopher Flowers, the US private equity investor, has emerged as a key player in the Royal Bank of Scotland-led consortium that has launched a €71bn ($95bn) break-up bid for ABN Amro, the Dutch bank.

Mr Flowers took part in the consortium’s negotiations with Bank of America several weeks ago, people familiar with the matter said. Two boutique investment banks in which Mr Flowers has stakes are also acting as advisers to Santander and Fortis, which have joined the consortium alongside RBS. Mr Flowers is understood to be acting as an informal adviser to the consortium, and is not acting as an investor or helping to finance the bid.