The productivity of the Monmouthshire workforce increased during the coronavirus pandemic, new figures show.
The figures, which highlight the gross value added by the workforce to the economy in areas across the UK, show massive regional disparities, with the majority of the most productive workforces based in London and the greater South East area of England.
Policy think-tanks have said the economic divide between London and the South East and the rest of the country "underline how pressing the levelling up agenda should be".
Office for National Statistics figures show workers in Monmouthshire contributed £34.72 GVA per hour worked in 2021 – up from £31.58 in 2019, before the coronavirus pandemic.
But this remained below the UK average of £38.33.
The figures also show significant regional disparity across the UK – 17 of the top 20 most productive local authorities were based in London or the South East, while none of the bottom 25 were from those areas.
The most productive place, Rushmoor in Hampshire, generated £77.92 GVA per hour worked and was more than three times more productive than Wyre Forest in Worcestershire at £23.84.
GVA is the final value of the goods and services produced in an area and is used to measure contribution to the national economy.
Paul Swinney, director of policy and research at Centre for Cities, said: "A key focus for the next Government should be to support every place to reach its potential, irrespective of where they are.
"The biggest cities outside of London, such as Birmingham and Manchester, are furthest from where they should be. It is fixing these places in particular that offers the biggest prize for the UK."
The Institute for Public Policy Research said the UK "continues to be the most regionally unbalanced large, advanced economy," adding this is not inevitable and is because of political choices.
Research fellow at the think-tank Marcus Johns said underinvestment in regions across the UK, the concentration of power in London, and under-resourced local government is "trapping us in an unequal and unproductive rut".
He added: "A serious upgrade is needed to the Government's levelling up agenda", including significant and long-term investment in issues such as transport and housing, as well as further devolution to enable growth and prosperity.
The Department for Levelling Up, Housing and Communities said levelling up is a "long-term programme of reform that sits at the heart of our ambition as a Government".
A spokesperson added the Government is "determined to spread opportunity everywhere" through investment in town centres and devolving more money and power to local leaders.
They said: "We have allocated almost £10 billion from levelling up funds since 2019, in addition to the £7.5 billion commitment to the nine city-based mayoral combined authorities in England.
"This includes providing bespoke funding packages for areas in greatest need of levelling up and establishing investment zones to further drive growth across the country."