There is no evidence that capital has been moving out of U.S. to U.K. or Europe merely on account of interest differential. Within a certain low range, capital flows are likely to be more influenced by outlook for growth and inflation than pure arbitrage even among industrial countries with full CAC.
Another point which has been forcefully put forward by several experts in the context of rising reserves, is that India should use its reserves for increasing investment for further development of the country rather than keep them as liquid assets.