Top Treasury civil servant: one in 10 staff has 'significant shortcomings' However, this decision was overturned after Mr Owen brought a successful internal appeal. Conrad Hallin, counsel for Mr Owen, suggested that as a result Mr Troup should not have led the proceedings that resulted in the civil servant being fired in May last year after more than 18 years" service at the Treasury. Sir Nicholas said all performance appraisal systems have "rough edges" but the Treasury's method of assessing staff was "reasonably fair." "Historically in the civil service, poor performance has not been addressed," he said. Much as I think the Treasury is a high-performing institution, I would be very surprised if less than 5 to 10 per cent of staff did not have serious development needs or significant shortcomings. Lawyers for Mr Owen, the Treasury's former head of National Insurance policy, allege that more senior civil servants changed advice he provided to David Gauke, a junior Treasury Minister, against his wishes and without consulting him. However, Mr Troup told the hearing that Mr Owen was dismissed because he "seemed to be incapable of working in a team environment" and relations between him and his managers had broken down. Sir Nicholas accepted the sacked tax expert was a "capable person with relevant experience in policy analysis" but rejected a suggestion that he could be reinstated by the Treasury. His inability to forge constructive relationships with managers will make it unlikely that anybody would offer him a job voluntarily [in the Treasury]. And I feel I would be failing in my duty of care to staff to impose him on a manager," he said in his statement. Sir Nicholas chaired a two-day appeal hearing brought by Mr Owen against his dismissal, after which he upheld the decision to sack him. The hearing continues