Octopus Energy is set to enter Japan as part of a strategic partnership valuing the energy supplier at $2.1bn (£1.6bn).

Its Octopus Energy brand and Kraken technology will be launched in the nation as part of a new joint venture with Tokyo Gas.

Tokyo Gas will take a 9.7pc stake in Octopus for $200m, while existing Octopus investor Origin Energy will inject a further $47m. Origin already has a 20pc stake following a deal in April that valued Octopus at more than £1bn.

Octopus was founded just five years ago but is now within striking distance of British Gas owner Centrica's £2.5bn valuation.

It has 5pc of the UK energy market serving 1.8m households, according to Ofgem.

This year Octopus has launched in the USA and Germany, and bought Upside Energy, a grid technology specialist. The company aims to have 100m customers globally by 2027.

In the UK it has launched Electric Juice, the electric vehicle roaming network, and partnered with Tesla on an energy plan.

Set up in 2015, Octopus serves more than 1.8m UK business with renewable electricity tariffs.

Chief executive Greg Jackson said: “We are delighted to announce our agreement with Tokyo Gas, one of the most respected and successful Japanese utilities, to launch Octopus Energy in Japan.

"This joint venture will bring our exciting approach to renewable energy and technology to the world’s largest competitive energy market, and the investment will turbocharge our mission to revolutionise energy globally."