Britain's largest grocer, Tesco , has today [Monday] launched its online e-tail service in the US with local partner Safeway , and company officials have made it clear that the US venture is to be a stepping stone for global expansion. The Internet tie-in with Safeway, California's largest supermarket chain and separate to the UK retailer, is said to offer consumers a e-shopping experience "almost identical, just painted different colours" to the UK's existing system. Safeway's online e-tail site,