Diageo started life as the seventh largest quoted company in the country, valued at pounds 23bn, bigger than Barclays but just behind BT. However, the new company got off to a disappointing start with the shares slipping 1.5p to 590p.
John McGrath, GrandMet's former chief executive and Diageo's chief executive, said: "This is the end of a long journey. It is sad day. On the other hand it is the start of a new journey and it is very exciting."
Diageo's first priority will be to integrate United Distillers and IDV, the spirits businesses of Guinness and GrandMet, which will lead to a wave of redundancies. Analysts expect many more job losses than the 2,000 Diageo has said will definitely go. "Until now UD and IDV have not been allowed to talk to each other. We will move like hell to sort out the businesses," said Mr McGrath.