From Tesco's Fresh & Easy adventure, to HSBC and M&S's ambitions and giant mergers, making it big in the US is not easy, says Hamish McRae. At first sight it’s a relief to see a UK-based firm thinking of taking over a US one, rather than the reverse. Next, what is it in our cultural relations that makes some cross-border mergers work and others a disaster? And, finally, to what extent does national strategic independence matter in a world that is so bound by global trade and investment? The firm is good at developing new drugs, especially for cancer, briefly becoming the most valuable London-listed firm this year.