LONDON (Reuters) - British prime minister-in-waiting Liz Truss will deliver a plan to lower taxes and boost economic growth, she said on Monday after winning the Conservative Party contest to replace Boris Johnson as the country's new leader.

"I will deliver a bold plan to cut taxes and grow our economy. I will deliver on the energy crisis, dealing with people's energy bills, but also dealing with the long term issues we have on energy supply," Truss said in a speech following the result.

(Reporting by Kylie MacLellan and William James, writing by Sachin Ravikumar)