£17.5m today is equivalent to £1m in 1958

Someone would need £17.5 million today to enjoy the equivalent lifestyle of a person with £1 million half a century ago, according to the Halifax.

There are an estimated 376,000 millionaires in the UK.

The value of £1 million will be cut by nearly two-thirds over the next 50 years if retail prices rise in line with the government's inflation target of 2% a year.

When today's 50 year old reaches the age of 60 in 2018, £1 million will be worth £820,348 in today's terms, based on inflation of 2% a year. This compares to today's 20 year old whose £1 million will be worth £452,890 when they are 60 years old in 2048.

Martin Ellis, chief economist at Halifax Financial Services, commented: "£1 million is still a lot of money, even though inflation has substantially eroded its purchasing power over the past half a century. Although £1 million cannot fund the lavish lifestyle it once could, it can still go a long way with careful financial planning."