OnePlus has announced that its OnePlus 2 and OnePlus X smartphones will arrive in a 60-minute delivery or, if it takes longer, the phone is free.

The marketing stunt is the result of a partnership between OnePlus and Henchman, a personal concierge service.

The "60 Minutes of Free" deal will be available in central London only and will take place on Thursday 21 January.

Orders for the £289 OnePlus 2 or £199 OnePlus X can be made via the Henchman website. Stocks will be limited but should get replenished at 10am, 12 noon and 2pm.

If your device arrives in longer than an hour you get it for free, presumably via a refund.

Carl Pei, OnePlus co-founder and head of global, said: "With '60 Minutes or Free' we are introducing a unique on-demand initiative that makes it faster and more convenient for our fans to get their hands on OnePlus devices."

Ryan Perera, co-founder and CEO of Henchman, said: "The OnePlus smartphones are the talk of the town, and we're really excited to have teamed up with OnePlus for this exclusive offer to any customers in central London - free delivery and the phone's free if we don't deliver in 60 minutes."

READ: OnePlus X vs OnePlus 2 vs OnePlus One: What's the difference?