It takes more than great assets to make a great business, and reputations built up over years can be shattered in days. For the best part of a decade and a half, BG Group PLC was once an oil major in the making. The company was the stock market’s pampered pet, with an enviable portfolio of oil and gas assets in some of the world’s most exciting new hydrocarbon provinces. The romance is now clearly over. Having removed the chief executive, Chris Finlayson, after only 16 months at the helm with no obvious replacement, BG Group looks a bit more like the Marie Celeste than a supertanker. Stock market pundits are speculating about break-up values and bets are being made on which bloated giant, ExxonMobil or Royal Dutch Shell, might have the cash and chutzpah to do the dirty deed.