Investment banks and asset managers expanded their UK-based staff significantly over the 12 months to June, shortly before what turned out to be a period of market turmoil, according to recently published figures.

The number of "Financial Services Authority-approved persons", that is, staff whose seniority or function requires them to be approved by the UK's financial services regulator, increased by at least 10% at eight investment banks and two asset managers over the 12 months to June, according to figures collated and just published by Imas, a UK corporate finance adviser.