Next year's iPhone 8, set to be a standout device marking the handset's 10th anniversary, could be Apple's last big hit for a decade, analysts have warned.

A note written for investors by Andrew Uerkwitz, a senior analyst at Oppenheimer, warns how Apple could quickly find itself on the back foot and unable to compete on a range of new fronts, such as artificial intelligence.

"We believe Apple lacks the courage to lead the next generation of innovation (AI, cloud-based services, messaging); instead [it] will become more reliant than ever on the iPhone," the memo, published by Business Insider, read.

Apple already relies heavily on the iPhone's success, with handset sales passing $28bn (£22bn) in the third quarter of 2016, way ahead of the $5.74bn generated by sales of Mac computers; iPads, iPods and the Apple Watch bring home even less money.

Uerkwitz went on: "We believe Apple is about to embark on a decade-long malaise. The risks to the company have never been greater." However, he added: "We believe its strong profitability, cash hoard for protection, and one last 'growth' hurrah from the tenth-anniversary phone will keep investors interested in the company."

Although Apple is still a hugely valuable and successful company, fears over its future have echoed around Silicon Valley and Wall Street for much of 2016. The company posted its first quarter of negative growth for 13 years in April, followed by its second and a 15% dip in iPhone sales in July.

Just one new product category, the Watch, has been introduced by Apple since the death of Steve Jobs in October 2011; before this the company enjoyed a decade of rapid-fire successes in the form of the iPod, iPhone and iPad, while the Mac range continued to impress in the background.

Now, as smartwatch sales fail to put in a dent in those of smartphones, investors and consumers alike are asking Apple for something new. Company boss Tim Cook has said repeatedly that augmented reality is a technology he and his team are very interested in, and just this week more evidence surfaced of Apple developing technology which could appear in a future autonomous car, albeit one unlikely be made by Apple itself.