The valuation of US tech giant Apple has continued to surge, surpassing the entire value of all the members of the UK's top share index.

Apple's shares rose 4% on Tuesday, valuing it at $2.3 trillion (£1.7tn), compared to the £1.5tn value of all the companies in the FTSE 100.

Apple shares fell back on Wednesday, but remained ahead of the London index at the close of trading on Wednesday.

It is just two weeks since Apple became the first US firm to be valued at $2tn.

Investors have been snapping up US tech stocks as demand for tech goods has surged amid the coronavirus pandemic.

More people are relying on technology to work and shop from home, and Apple has been one of the major beneficiaries.

The iPhone-maker has seen its share price more than double since March, when panic about the coronavirus pandemic swept the world's stock markets.

Demand for Apple's shares was also said to be boosted on Tuesday by company's decision to divide its shares, swapping four new ones for every old one investors held. The move is expected to make it easier for individuals to invest.

By contrast, market-watchers said London-listed companies, which include lockdown-hit oil companies and banks, have performed sluggishly compared to the runaway share prices of big US-listed tech firms.

"The FTSE 100 is a dinosaur, full of rather lumbering old-world stocks with precious little growth to offer," said Neil Wilson, chief market analyst for Markets.com. He added that it is also "a very good proxy for the global economy, which we know is on its knees".

With the exception of Ocado, "there is no tech to speak of, which is where the real money has been made this year," he added.

"Whilst the US has Zoom, we have BT and Vodafone. The US boasts Netflix and Amazon - the FTSE can muster ITV and Sainsbury's."

The FTSE 100 is trading at 5,972 points, down 22% from its 2020 high of 7,675 in January.

By contrast, the Nasdaq index in the US, which includes many large tech companies, hit a fresh record on Tuesday. It has almost doubled since the collapse in share prices in the immediate aftermath of the coronavirus outbreak.

Some investors have warned that that all markets - including those trading in stocks, bonds and commodities - are overvalued at the moment.

Stimulus from central banks to support struggling economies - including quantitative easing and historic low interest rates - have buoyed the value of many companies and assets.

In another sign of booming tech valuations, Tesla's 12% stock gain propelled founder Elon Musk's personal fortune to $115bn this week, briefly making him the third-richest person in the world, according to Bloomberg. He temporarily overtook Facebook founder Mark Zuckerberg.