The figures will be welcomed by the Government, as Labour vowed in its manifesto to achieve the highest sustained growth in the G7.
However, they will also raise questions over the Chancellor’s proposed tax increases, as she has claimed radical action is needed to fix the alleged £22bn black hole left by the Conservatives.
Ms Reeves has been criticised for talking down the economy in recent weeks, outlining at the end of July how she has inherited “the worst set of circumstances since the Second World War” with high levels of debt and an economy “only just coming out of recession”.
Following the OECD’s latest upgrade, Ms Reeves said: “Faster economic growth figures are welcomed, but I know there is more to do and that is why economic growth is the number one mission of this Government.
“Next month’s Budget will be about fixing the foundations, so we can deliver on the promise of change and rebuild Britain.”
The latest forecasts come after official data shows the UK economy grew by 0.7pc in the first quarter of the year and by 0.6pc between April and June, driven by strong growth in the services sector.
Increased household spending has been key to recent growth, the OECD said, with customers benefiting from real wage rises as inflation falls.
The OECD’s prediction is higher than the 0.8pc growth forecast for the UK this year by the Office for Budget Responsibility (OBR), the Government’s spending watchdog, but still lower than the OBR’s forecast of 1.9pc growth in 2025.
Gerard Lyons, the chief economic strategist at Netwealth, said: “The Chancellor is too pessimistic. She was justified in highlighting the poor fiscal position we are in and the high level of debt, but she was wrong to talk down the economy because, as the figures show, the economy was relatively strong in the first half of the year.
“There is no doubt that the stronger growth picture for this year helps the Chancellor because it gives her more room for manoeuvre.”
Shoring up the public finances will be much easier if the economy is growing at a faster rate because this will naturally increase tax revenues, reducing the need for borrowing.
However, the real test will be the OBR’s own updated economic forecasts, Mr Lyons added. The Chancellor will receive the pre-measures fiscal forecast two to three weeks before she announces her Budget.
The UK’s latest upgrade was in stark contrast to the OECD’s projections for Germany, which cut its growth forecast from 0.2pc to 0.1pc for 2024.
It blamed this on a significant downturn across the country’s industrial sector, as well as high rates of savings among households.