UPDATE 1-Citi's King to co-head corporate finance at BarCap

* King joins Ros Stephenson as co-head of corporate finance

* Joseph Gatto moves to chair U.S. investment banking

LONDON, Oct 27 (Reuters) - Barclays Capital named former Citigroup banker Tom King as co-head of corporate finance -- another London-based senior hire by the Barclays (BARC.L) unit as it looks to become a global, full-service investment bank.

King, who left Citigroup (C.N) in September, will work alongside New York based Ros Stephenson, with both reporting to Hugh "Skip" McGee, head of global investment banking.

Joseph Gatto, previously co-head of corporate finance in New York with Stephenson, will become chairman of investment banking for the Americas, focusing on "building and expanding senior relationships" with BarCap clients, the bank said.

Barclays Capital Chief Executive Bob Diamond is seeking to transform BarCap from a debt-focused institution to a top player across investment banking, building on last year's purchase of the U.S. operations of Lehman Brothers.

King was most recently Citigroup's head of banking for Europe, the Middle East and Africa (EMEA). He made his name as one of Wall Street's leading telecoms bankers during the 1990s merger boom.

His appointment follows the hires of senior mergers bankers and equity capital markets specialists from Citigroup, Deutsche Bank, UBS, Rothschild and elsewhere.

(Reporting by Quentin Webb and Douwe Miedema; Editing by David Cowell)