Simon Hogan*, a 53-year-old helicopter engineer from Hampshire, credits the success of his self-invested pension to Telegraph Money.

“I have picked most of the funds in my Sipp based on the tips that appear in these pages,” he said. “And they have been some of my best performers. My biggest holding, Guinness Sustainable Energy, has gained around 18pc since I read about it in the paper.”

Mr Hogan took control of his pension savings three years ago after he grew frustrated with poor returns from his company scheme.

“It was barely keeping up with the rest of the market,” he said. “I thought I could run it better myself.”

But with retirement just four years away, Mr Hogan is now unsure whether his portfolio will continue to grow, as chatter of a market bubble persists. He has a large proportion of his savings invested in US stocks.

“How do I know if my funds will keep going up? I am worried that I am not diversified enough to protect myself from a crash. I’m not an adventurous investor, I just want my money to keep growing steadily.”

Mr Hogan added that he was waiting to breakeven on his investment in China, where he has lost around a fifth of his money.