Richard Branson has reiterated his plan to fly with his children on the inaugural flight of his long-planned commercial space operation, Virgin Galactic, despite the relatively untested nature of the technology and a departure date which has slipped repeatedly.

"Everybody who signs up knows this is the birth of a new space programme and understands the risks that go with that," Branson said in an interview for Weekend magazine at Virgin Galactic's base in the Mojave desert north of Los Angeles. "But every person wants to go on the first flight."

While insisting his plan is credible and the first flight, reaching 62 miles above the Earth, will take place later this year – he has previously promised it for this autumn – Branson admits how difficult it has been to overcome the exacting safety expectations of a commercial space operation.