Ashurst is axing six assistants from its corporate department on performance grounds.

The move comes as the firm prepares to unveil a sharp drop in profits after what insiders admit has been a difficult year for its flagship corporate arm.

All six assistants hail from the firm's corporate practice – and are understood to be relatively junior, averaging at around the two-year qualified level.

A spokesman for the firm, told Legal Week: "We have decided to let a handful of lawyers go within the next three months."

Sources at the firm said the assistants were being encouraged to look for another job after it was assessed that they would "probably not make it to partner-ship level".

The move is further evidence of a toughening up of Ashurst's approach to performance after a year in which many of its core private equity clients had been relatively inactive.

The firm has also conceded that some partners have been moved down the lockstep in a bid to raise the performance bar.

"It has been a tough year for us. I think everybody would concede that we have been a little unlucky," said one Ashurst partner.

"Then again, the year before we had a good year, so there is a swings and roundabouts aspect to this."

A private equity partner at a rival firm said: "It has been a bad year for law firms, but Ashurst has been slightly unluckier than other firms. On the corporate front it has not had much deal flow, so it is not very surprising it is letting people go."

Last year the firm posted an above average performance, with average profits per partner dropping by 2% to £590,000 and against a 6.5% increase in turnover.