David Cameron's visit to India this week seeks to restart a once-strong alliance. Historical and cultural ties remain, but for the past decade the sense in Delhi has been that this is a relationship in decline. Britain's share in India's trade and investment has fallen. David Miliband's clumsy comments on Kashmir angered many by implying Indian responsibility for the mess in Afghanistan. As the US has become the country to emulate, Britain has become marginal to Indian political consciousness.

The Indian government will be too polite to say it, but there is a lot of (perhaps premature) condescension in India towards Britain's shrinking role in the world. Where once Britain educated India's ruling classes, now most head to the US. The economist Amartya Sen's move from Harvard to become Master of Trinity College, Cambridge, was described in India as a move from a powerhouse to a museum. In subtle ways Indians are constantly comparing the ability of the US to cut imaginative deals that benefit India directly with that of other nations. And on the quiet, the dynamism of their new relationship with the Americans has inspired hope in many Indians that they may come to replace the United Kingdom as the US's special ally among the world's democracies.

Mr Cameron's extensive delegation hopes to reverse this trend, and he has some reason for optimism. Both countries naturally want to deepen their economic relationship. India will continue to grow in excess of 9 per cent, while both its burgeoning middle class and an unprecedented level of new investment in military hardware will make India a vital export market for Britain. Indian outbound investment, meanwhile, is still looking to tap into Britain's research and design capabilities.