Narendra Modi, the prime minister elect of India, has invited the leader of the country's hostile neighbour Pakistan to his inauguration in Delhi next week, in what analysts have hailed as a bold step to launch a policy of regional engagement.If Nawaz Sharif were to attend the ceremony, it would be a first in the history of the two states, which both have nuclear arsenals and have fought four wars since gaining their independence from Britain in 1947. Repeated bids to improve relations have failed, though there have been incremental gains over the last decade.