THE Range Rover Evoque Convertible, the world's first premium compact open-top, will go on sale next year.

And the model, which will be built at the company's Halewood plant in Liverpool, has already undergone a unique underground testing programme.

The original five-door version of the Evoque was driven through Liverpool'ss Edge Hill tunnel - the first of its kind in the world to be bored beneath a major city - during its launch in 2011.

Now the first prototype of the convertible has descended 40 metres below the streets of London, after being given exclusive access to the 26-mile network of Crossrail tunnels for a development test with a difference.

Land Rover's engineers were allowed the opportunity to drive the disguised Evoque Convertible with its roof lowered in complete privacy.

The convertible was lowered into the tunnel network by crane, before negotiating a range of obstacles through the 6.2-metre diameter cavern.

Land Rover Programmes director Murray Dietsch said: "The tunnels are still under construction, so we had a unique opportunity to explore the vehicle's all-terrain ability in unchartered territory."

The company intends to announce further details about the car later this year.