Britain's richest people are wealthier than ever before with a combined fortune of STG518.975 billion ($A947.29 billion), according to this year's Sunday Times Rich List.

Amid talk of the "squeezed middle", the 1000 richest Britons now own the equivalent of a third of the country's gross domestic product (GDP), with their combined wealth rising 15.4 per cent on last year's total of STG449.654 billion.

A minimum of STG85 million is needed to even be considered for the list this year - compared to STG80 million in 2008 at the height of the pre-crash boom and STG75 million last year.

To get into the top 500, the rich need STG190 million - double the STG80 million required in 2004 and up STG30 million from the STG160 million cut off point for last year's list.

Philip Beresford, who has compiled the ranking since 1989, said: "I've never seen such a phenomenal rise in personal wealth as the growth in the fortunes of Britain's 1,000 richest people over the past year.

"The richest people in Britain have had an astonishing year.

"While some may criticise them, many of these people are at the heart of the economy and their success brings more jobs and more wealth for the country."

Most distinguished among the old money names, the Queen had a sterling year as she added STG10 million to her personal fortune and is now ranked 285 with STG330 million.

Well-established Rich List millionaires such as Jamie and Jools Oliver had their worth go up by STG90 million to STG240 million, ranking them at 396, as the celebrity chef's restaurant chain, TV appearances, cookbook sales and Jool's childrenswear range continued to pay dividends.

South African insurance tycoon Douw Steyn, the money behind the wild success of the meerkat TV advertising campaign for comparethemarket.com, saw his wealth go up by STG50 million to a total of STG600 million, ranked 170.

Former Tesco boss Sir Terry Leahy, who stepped down at the supermarket chain in 2011, was among the new entrants with a worth of STG100 million, ranking at 863.

The digital economy also showed its growing purchasing power as four members of King Digital Entertainment, which is behind the addictive Candy Crash game, joined the list for the first time too.

They include entrepreneur Mel Morris, who came in at 238 with a STG430 million fortune, and King's chief executive Riccardo Zacconi, ranked 271 with STG354 million.

The masterminds behind best-seller computer game Grand Theft Auto, Rockstar Games supremos and brothers Sam and Dan Houser, were new entries at 947 with a joint fortune of STG90 million.

Meanwhile, US film producer Harvey Weinstein and his British former model turned designer wife Georgina Chapman also made the grade for the first time with a joint fortune of STG115 million, ranked 788.

Entertainers featured heavily in the 50 Young Rich list for those aged 30 and under.

Former Harry Potter star Emma Watson, 24, is now estimated to be worth STG30 million, up STG3 million on last year, as she builds a career for herself as a Hollywood leading lady.

Husband and wife Marcus Mumford 27, and Carey Mulligan, 28, joined the young list for the first time with a joint fortune of STG13 million from their music and films.

Last week it was announced that the list's compilers had found that the number of billionaires living in Britain has risen to more than 100 for the first time.

Some 104 billionaires are now based in the UK - more than triple the number from a decade ago - with a combined wealth of more than STG301 billion.

It means Britain has more billionaires per head of population than any other country, while London's total of 72 sterling billionaires is more than any other city in the world

The 26th annual Sunday Times Rich List is based on "identifiable wealth" - including land, property, other assets such as art and racehorses, or significant shares in publicly quoted companies.

It excludes bank accounts, which the Sunday Times has no access to.