* Jobs transferred from UK to cut costs
* More cuts expected in coming months
* Decision is "ruthless" -trade union (Adds bank, union comment, share price)
By Andrew MacAskill and Lawrence White
LONDON, May 16 (Reuters) - HSBC, Europe's largestbank, started laying off 840 information technology workers inBritain on Monday, the first big tranche of redundancies under arestructuring plan that will eliminate 8,000 British jobs by theend of next year.
Most of the staff affected were being informed about thecuts on Monday, according to a source familiar with the matter.
The majority of the roles are based in London, Sheffield andTankersley and all the jobs will disappear by the end of thisyear, the source said.
"As part of a global relocation exercise, around 840non-customer-facing IT roles will transfer from the UK to othersites around the world," John Hackett, chief operating officerof HSBC UK, said in a statement.
The bank unveiled its three-year restructuring plan lastyear, designed to pare back its sprawling global network byshutting underperforming businesses to improve earnings hurt byhigh compliance costs, fines and low interest rates.
The restructuring will eventually eliminate one job in fivearound the world, and around a sixth of jobs in Britain.
When the restructuring plan was announced, Chief ExecutiveOfficer Stuart Gulliver said most of the job losses in Britainwould come from employees leaving on their own accord.
The Unite union said many of the jobs will now be offshoredto lower income countries such as India, China and Poland.
"HSBC's decision to axe so many IT jobs is as ruthless as itis reckless," said Dominic Hook, national officer at Unite. "AsIT glitches across the banks continue to prove, it is ultimatelythe customers who will suffer the consequences."
Problems with HSBC's computer system cut customers off fromaccess to online accounts on two occasions this year.
HSBC has 47,000 UK workers at the end of December, accordingto its most recent annual report. More cuts are expected overthe coming months as the bank continues to consolidate IT andback office operations, the sources said.
HSBC's shares remained flat on Monday, in line with thebenchmark FTSE 100 index. The lender's shares havefallen 20 percent this year as tough global market conditionshave hammered trading revenues for banks worldwide. (Editing by Sinead Cruise and Peter Graff)