Liz Truss has vowed a "bold plan" to address tax cuts and the energy crisis

New Delhi: Shortly after Liz Truss was announced as the UK's next prime minister on Monday, Prime Minister Narendra Modi tweeted a congratulatory message to the Conservative party leader.

"Congratulations @trussliz for being chosen to be the next PM of the UK. Confident that under your leadership, the India-UK Comprehensive Strategic Partnership will be further strengthened. Wish you the very best for your new role and responsibilities," PM Modi posted on Twitter.

The foreign secretary, 47, comfortably beat her rival, former finance minister Rishi Sunak, by about 57 to 43 percent after a marathon summer-long contest decided by just over 170,000 Conservative members - a tiny sliver of Britain's electorate.

Ms Truss, in a short victory speech at the announcement in a central London convention hall, said it was an "honour" to be elected after undergoing "one of the longest job interviews in history".

She has vowed a "bold plan" to address tax cuts and the energy crisis.

Ms Truss will be only the UK's third woman prime minister following Theresa May and Margaret Thatcher.