Two-thirds of the UK's most successful companies during the last Government were based in London and the South-East, research today shows.
Experian, the information services company, said 130 of the top 200 UK companies in the four-year period came from the region.
That compares with just two firms in Wales, nine in Scotland and 13 in the West Midlands.
Experian said the figures highlighted "imbalances" within the UK economy, with London and the South-East and service firms dominating the rankings.
One in four firms were involved in financial services, with a further 33 dealing in business services.
Just 13 IT companies featured in the list and only one was specifically involved in the internet.
Experian used sales growth, pre-tax profit growth, increase in profit margin, and return on capital for the study.
It found that Berkeley Commercial Developments, based in Cobham, Surrey, met those criteria more successfully than any other company.
Leeds-based property firm Manormount was second, followed by three London firms - property development business Glengate Holdings, financial services business Clareville Capital and business services operation Berkley Estates.
Every size of company features in the study, with retailer Matalan reporting sales of £433.8 million in its latest financial year compared with the smallest firm, Ruane Securities, with sales of £131,000.
Arsenal Football Club, Auto Trader magazines and Pizza Express were among other companies in the top 200.
Peter Brooker, Experian spokesman, said companies in the list had been successful for a variety of different reasons.
But he added: "The common factors are dedicated, single-minded managements, which have anticipated their markets and have the ability to adapt to rapidly changing circumstances."
Experian said the most successful location outside London was Edinburgh, with five companies, followed by Chester and Birmingham, both with four firms.
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