LONDON, March 3 (Reuters) - Britain’s finance minister Rishi Sunak on Wednesday launched a new state-backed loan scheme for businesses hit by the COVID-19 pandemic, replacing existing programmes that have seen struggling businesses borrow some 73 billion pounds so far. The new scheme will offer loans from 25,000 to 10 million pounds ($13.97 million), with an 80% state guarantee, replacing the previous ‘bounce back’ scheme aimed at small businesses and programmes for larger firms.