Britain's richest people are wealthier than ever before, with a combined fortune of £518.975bn, according to this year's Sunday Times rich list.

Amid talk of the "squeezed middle", the 1,000 richest Britons now own the equivalent of a third of the nation's gross domestic product (GDP), with their combined wealth rising 15.4% on last year's total of £449.654bn.

A minimum of £85m is needed to even be considered for the list this year – compared to £80m in 2008, at the height of the pre-crash boom and £75m last year.

To get into the top 500, the rich need £190m – double the £80m required in 2004 and up £30m from the £160 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 £10m to her personal fortune and is now ranked 285 with £330m.

Well-established rich list millionaires such as Jamie and Jools Oliver saw their worth go up by £90m to £240m, 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 £50m to a total of £600m, 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 £100m, 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 £430m fortune, and King's chief executive Riccardo Zacconi, ranked 271 with £354m.

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 £90m.

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 £301bn.

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 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.

Chris Leslie MP, Labour's shadow chief secretary to the Treasury, said: "No wonder the super-rich have got much richer over the last year when David Cameron has given millionaires a huge tax cut.

"Yet at the same time working people have continued to face a cost-of-living crisis and are £1,600 a year worse off since 2010.

"Labour is determined to ensure all working people feel the benefits of economic growth, not just a few at the top."