LONDON (Reuters) - Barclays (>> Barclays PLC) Finance Director Chris Lucas is stepping down from the bank six months ahead of his scheduled retirement, citing health reasons, the bank said on Wednesday.

Lucas, aged 52, who has been finance director for a tough six years that spanned the global financial crisis, announced his retirement in February.

"Whilst I had hoped to be able to continue working until early next year it is now clear to me that with my health as it is this will no longer be possible," Lucas said in a statement.

The bank announced in July that JPMorgan (>> JPMorgan Chase & Co) executive Tushar Morzaria would take over as finance director in February next year.

He will now take up his appointment on 15 October. Peter Estlin, Barclays' group financial controller, will serve as acting finance director until Morzaria's arrival.

Lucas' departure comes just weeks after the British bank said it would raise 5.8 billion pounds from its shareholders to plug a larger-than-expected capital shortfall identified by Britian's financial regulator.

The rights issue, due to be launched in September, will be the biggest by a British bank since 2009 and will offer shareholders one new share at 185 pence for every four currently owned.

Barclays shares closed at 284 pence on Tuesday.

"I am very grateful for his support, advice and wisdom during my first year as Chief Executive. Chris has helped navigate our company through many challenges during his six years with the business," Chief Executive Antony Jenkins said.

Lucas is one of four current and former employees being investigated by UK authorities regarding a capital injection by Qatar in 2008.

Lucas's departure has no links to the ongoing investigations into Qatar, sources told Reuters at the time of Lucas' original retirement announcement in February.

He was the only one of Barclays' executive directors to hold onto his job after the bank was fined $450 million in June 2012 for rigging the Libor global benchmark interest rate.

(Reporting By Anjuli Davies, editing by Sinead Cruise)

Stocks treated in this article : JPMorgan Chase & Co, Barclays PLC