Natasha Bedingfield’s ‘Unwritten’ was inspired by the Beatles. The 42-year-old pop star enjoyed huge success with her 2004 single, and she’s now revealed the inspirations behind her chart-topping track. Natasha told the Guardian newspaper: “I was whisked off to Los Angeles to work with songwriting mentors, which upped my game but meant I missed my younger brother Joshua’s 14th birthday. I hadn’t had a moment to send him a gift, so I decided to write him a song. ‘Unwritten’ was written with a 14-year-old in mind. “At that age, you’re desperate to be taken seriously but at the same time everyone…