When JPMorgan teamed up with City stockbroker Cazenove in 2004, the British firm with roots back to the Victorian era was an all-powerful force among UK Plc.

It was corporate broker to 246 companies in 2005, over 100 more than its nearest competitor, UBS, data provider Adviser Rankings found. Now fully integrated with the Wall Street bank, JPMorgan Cazenove remains the top broker for FTSE 250 firms, but a swathe of new aggressive new entrants and changing client demands have transformed this very British corner of investment banking over the years.