UK firms created over 700,000 jobs in 2014-15 - with almost a quarter of them located in London.
Research from the Enterprise Research Centre has found that of the 709,174 net new jobs created in the period, 23 per cent of them came from London firms.
Total private sector employment rose to 21.6m as a result - the highest number ever for the sector.
London and the South East also became home to the highest number of new start ups, but a higher proportion of start ups based in Cumbria and North East Scotland made it past their third year.
Despite London's considerable contribution, Professor Mark Hart, deputy director of the ERC, said the results show job creation is spread across the UK. High proportions of the fastest growing businesses were found in Scotland, Wales, and Northern Ireland.
"Nor is it restricted to certain types of 'fashionable' high-growth firms - there's a complex growth pipeline of companies in every corner of the country that have different support needs based on their individual ambitions," Hart said.
Business minister Margot James said: "This research shows vibrant business growth across the nation and the highest ever level of private sector employment.
"The government will shortly publish the industrial strategy green paper to boost productivity, create more jobs and drive economic growth. The new £23bn national productivity investment fund will help to ensure our economy is fit for the future, and an extra £400m for the business bank will unlock investment for innovative firms across the country."
The national productivity investment fund was announced in chancellor Philip Hammond's Autumn Statement. The £23bn will be spent over five years seeking to improve UK productivity - which is lagging behind the US and Germany - and will be funded by additional borrowing.