Research reveals entrepreneurs, city workers and sportsmen are among the demographic's highest earners.

The number of people in the UK under the age of 30 earning more than £1 million ($1.2 million) annually increased by a third to 400 last year, compared with 300 the year before, according to new data from Salisbury House Wealth.

Among the higher earners in this age group are entrepreneurs, city workers and sportsmen, the UK-based firm said.

In comparison, the number of over 30s earning more than £1 million per year has increased by 31 per cent, rising from 10,200 to 14,800, supporting the idea that this demographic is “still way ahead” of the under 30s in terms of wealth creation.

The contrast between millennials and baby boomers in terms of how they manage their wealth is currently a hot topic of industry discussion. The under 30s demographic has been dubbed the “start-up generation”, due to youngsters’ appetite for setting up their own businesses, according to Salisbury House Wealth.

Earlier this month, research from St James’s Place showed that nearly half of the UK’s millennials, or those aged between 18 and 34, find the idea of running their own financial advisory business attractive.

Last month, SEI Private Wealth Management research found that ultra-high net worth Americans have clear-cut generational approaches to financial management, with baby boomers setting the standard for the millennial generation.

In other findings, the number of under 30s earning more than £43,000 is also 52 per cent higher than it was five years ago.

“The trend in start-ups, as well as the monetisation of online media has had a significant influence on the earning potential of the under 30s,” said Tim Holmes, Salisbury House Wealth’s managing director.

The firm cautioned that despite recent success stories of start-up founders and online millionaires, it is unknown whether these sources will continue to provide high income in the future.

The research is based on the latest available data for the 2013-14 tax year and may exclude payments to companies held offshore where funds are not remitted to the UK.