Shire's James Bowling will leave the Dublin-based firm at the end of the first quarter of 2015 and become chief financial officer at Severn Trent to replace retiring CFO Mike McKeon.

His departure hints at the disruption caused by AbbVie's on-off deal to acquire Shire, with the prospect of becoming part of a Chicago-based group prompting some Shire executives to look elsewhere for opportunities.

AbbVie's move for Shire, a leader in drugs to treat attention deficit disorder and rare diseases, was announced in July amid a spate of deals in the pharmaceutical sector largely driven by tax savings.

But AbbVie's U-turn after the U.S. government proposed new tax rules has now focused attention on Shire's future as an independent company and its own potential for making acquisitions, or else becoming a target once again.

Bowling took over in the CFO role at Shire on an interim basis on March 1 when the finance director at the time, Graham Hetherington, stepped down.

Shares in Shire were down 1 percent lower at 0737 GMT (8.37 a.m. BST), while Severn Trent shares were flat.

Severn Trent also said on Monday that it would cut three director posts with effect from Jan. 23, leaving two executivedirectors and six non-executive directors.

(Reporting by Karolin Schaps; additional reporting by Ben Hirschler; editing by Kate Holton and Louise Heavens)