Diageo, the world's biggest spirits company, has shunned financial advisers including long-standing favourite UBS, to negotiate an option to sell shares worth £1.15bn (€935m) in General Mills, a US food brands group.

Diageo has bought put options for 25 million General Mills shares from Lehman Brothers with an exercise price of $51.56 a share. It will pay a premium of $5.56 a share on settlement. The option is exercisable from November 4 for five days.