Jim Armitage: The pressure mounts on GSK’s unstable compound

For all his honours and decorations, Sir Andrew Witty’s long stint running GSK has hardly been a blockbuster.

True, he has stewarded the drugs giant through a generation of patent expiries and ever-greater pressure on prices in the US. And, true, he has avoided the temptation to blow the balance sheet with ego-driven takeover deals.

But, as many shareholders will tell you, he has also been consistently over-optimistic about the shape of the business and, although earnings growth is returning now, has regularly disappointed on the execution of his strategies.

While he has built up two divisions with big, reliable future earnings (consumer medicines and vaccines) GSK’s pharmaceuticals pipeline remains poor. And for all that, he’s earned over £40 million since starting in the job.

There are now noisy calls for the business to be broken up. That would seem wasteful, given the shared distribution networks and facilities between the divisions.