Jefferies has put 15 research and sales staff in London at risk of redundancy, while it has also emerged that the US investment bank's head of international equity sales has left following an investigation into possible tax fraud.

The research job losses include cuts to the insurance, consumer, technology and healthcare teams, according to sources familiar with the situation, and include around four publishing analysts. In addition, around three sales staff have been put at risk, according to two of the sources.