The Career Horizons event - a kind of internal career fair - is the central plank of KPMG's strategy to tackle what it described as 'a dearth of qualified talent in the market'.

It said that with costs of around £25,000 to hire a senior manager it was fighting to retain 'precious talent' it had invested in developing.

Ernst & Young said it also considered the shortage a 'real area of concern' which it said was re-emerging, having been masked by tough market conditions.

Recruitment experts Harvey Nash said professional service firms had experienced an increasingly competitive environment since September.

James Crawley, a senior consultant, said that the recent downturn in the sector had reduced the recruitment pool, rendering initiatives to retain staff 'essential'.

'The glamour of working for Big Four firms has worn off significantly, and that has been compounded by major accounting scandals. Firms have had a luxurious time but they are now having to target people,' he said.

Keith Dugdale, KPMG director of recruitment, said: 'We need to aggressively sell the opportunities within the firm so employees don't move to industry and investment banks.'