Rating Whitehall's performance has been challenged by the Government's modernisation minister. Cabinet Office minister, Liam Byrne, told MPs last week that the Civil Service's performance had improved ‘radically', but claimed departments still needed to improve on how they delivered change. Rating central government performance has become a hot issue. Mr Byrne's comments coincided with research from the National Audit Office, which concluded that the assessment of departments bore no relation to their ability to hit targets. Mr Byrne told the Commons public administration committee that Whitehall was still struggling to go beyond the traditional silos, and slow at tackling issues quickly. But he rejected the idea by former industry minister, Lord Digby Jones, that the Civil Service could be reduced to half its size. He said: ‘The central Civil Service is still not good enough at driving the business of delivery rapidly. ‘Second, its policy-makers are not entrepreneurial or innovative enough. I think things are much better than they were, but they could be much better than they are today. ‘And third, I still think the centre of government isn't good enough at joining together integrated policy delivery.' Head of the civil service, Sir Gus O'Donnell, is due to give his evidence to the committee at the end of the month.