Standard Chartered's new chief executive Bill Winters has plans to cut about 1,000 of the bank's most senior staff to reduce costs, according to a memo sent to staff.

The cull shows the scale of the overhaul Mr Winters is planning at the Asia-focused bank, which he has said needs to speed up decision-making on costs, people and strategy, and improve its risk management and profitability.

The memo states Mr Winters wants to reduce by one quarter the number of staff graded in bands one to four. Those bands cover bankers at director level and higher and include about 4,000 staff.

"Our situation requires decisive and immediate action," Mr Winters told staff. "Each member of the management team has a mission to drive through improvements in our returns and part of this will be further streamlining of our organisation."

Mr Winters, a former JP Morgan investment bank boss who took over in June after the ousting of predecessor Peter Sands, said the bank would also make disposals and cut clients.

Disposals would be in areas where the bank was "not differentiated", or an activity or location "was not critical to a core strength."

Earlier this month Martin Gilbert of Aberdeen Asset Management, the second largest shareholder in Standard Chartered, voiced his support for Mr Winters.

The Herald: Martin Gilbert, chief executive of Aberdeen Asset Management. Picture by Colin Mearns.

The bank has had a troubled three years due to weakness in many of its key emerging markets, rising losses from bad loans in India, China and on commodities, as well as fines from US regulators and strained relations with shareholders.

"We lost some discipline during that time, leading to our recent problems with loan impairments and relatively high expenses," Mr Winters said in the memo.

He is expected to outline more details on his plans to investors and staff in November or December.