'Once the budget has been approved, it must then be executed as planned with appropriate management control and accountability systems in place. This involves the development of incentive structures and sanctions, and systems of rules to control spending that ensures the efficient and effective use of funds'.
'Budget execution is the point at which responsibility moves away from the centre to a diverse network of agencies and departments. While building the capacity of the staff that work in these agencies will typically be an important step, there is also a need to ensure that staff understand their responsibilities and how they support the wider goal.'
From OPM page http://www.opml.co.uk/issues/budget-execution