Further signs of economic optimism emerged today as a business group predicted stronger than previously expected growth for this year.

The British Chambers of Commerce (BCC) raised its gross domestic product (GDP) estimate to 1.3% for the year from its previous 0.9%.

Unemployment will fall and government borrowing dip, the BCC said.

But it warned that the economy could yet be derailed by global jitters and urged the Government and Bank of England to do everything possible to ensure the recovery moves from “good to great”.

Britain’s growth prospects have been boosted by increasingly upbeat data in recent weeks, including an official upgrade to growth between April and June from 0.6% to 0.7%.

Services, manufacturing, construction and agriculture all expanded, the first time Britain has been firing on all cylinders for nearly three years.

The new quarterly forecast follows another upgrade three months ago when the BCC raised its growth prediction from 0.6%. It also lifted growth forecasts for 2014 and 2015 to 2.2% and 2.5% respectively.

Household consumption should grow by 1.7% this year and 2.3% next year as weakening inflation eases the squeeze on incomes, according to the BCC.

Director general John Longworth said: “Unfortunately, however, the recovery is not yet secure. We have had false dawns in recent years and although this upturn appears to be on stronger ground, we must be aware that complacency could lead to setbacks.”

The services sector, which makes up about three-quarters of the economy, will expand by 1.9% this year and 2.6% next year, the BCC said.

But manufacturing will shrink by another 0.8% this year and construction will decline 1.2%, it predicts.

It also expects unemployment to fall to 2.45million by the third quarter of next year, 200,000 lower than its prediction in May.

It reckons unemployment will hit the Bank of England’s threshold of 7% - when the bank will consider raising interest rates - in the fourth quarter of next year. This is earlier than its prediction of late-2016.

The BCC also forecast that net public sector borrowing will come in at £116.3billion this financial year, £3.5bn lower than the Office for Budget Responsibility’s prediction in March.