* Andy Street chosen as Conservative Party candidate
* Will step down as John Lewis MD on Oct 28
* Firm will name successor "in due course" (Adds statement from John Lewis)
LONDON, Sept 30 (Reuters) - British department store chain John Lewis will have to appoint a new leader after Managing Director Andy Street was chosen by the ruling Conservative Party as its candidate for mayor of the West Midlands in central England.
Street, who has been with John Lewis for 31 years, nine as MD, was formally selected by local Conservative members on Thursday, the party said in a statement.
The employee-owned John Lewis Partnership, which also owns upmarket supermarket Waitrose, said he would step down from his role on Oct. 28 to fight the mayoral election which will be held in May next year.
It said Street's successor will be announced "in due course".
Analysts say frontrunners to succeed Street are his former lieutenant Andrew Murphy, who is now the partnership's productivity director, current retail director Mark Lewis and commercial director Paula Nickolds.
"Andy has led John Lewis brilliantly and leaves the brand with great momentum for the future," said the Partnership's chairman Charlie Mayfield.
Earlier this month the department stores business reported a 31 percent fall in first-half operating profit despite a 4.5 percent rise in sales. The profit fall reflected increased investment, higher staff costs and lower prices.
However, the firm said it was confident it would outperform the market in the second half when the majority of its sales and profit are delivered. (Reporting by James Davey; Editing by Mark Trevelyan and Paul Sandle)