The Chancellor of the Exchequer decides the dates of our forecasts when he decides the date of the Autumn Budget (usually in late November or early December) or the Spring Statement (usually in mid-March). Under normal circumstances, the Chancellor is required to give us 10 weeks’ notice when requesting a forecast. The Treasury informs the Treasury Select Committee and Parliament of the date at the same time, or as soon as possible afterwards if Parliament is in recess. Please refer to the Treasury website for announcements.
"It is the duty of the Office to examine and report on the sustainability of the public finances"