Taxpayer-backed RBS plans to cut 40 percent of permanent IT staff, or 650 jobs, and 65 percent of contractors which equate to 230 roles, Unite said in a statement.

Unite said there would be 950 full-time IT staff by 2020, compared with 2,200 in 2016, but a spokeswoman for RBS said it had not yet begun any formal consultations on job cuts and no numbers had been set.

"As we develop long term plans for our technology business, we have in the interests of transparency, started to share our emerging proposals on a future operating model with Unite. We have not consulted on any headcount reduction, instead sharing a direction of travel with Unite which is subject to change," the RBS spokeswoman said.

"Our proposed plans are designed to reduce the number of contractors we employ and strengthen our permanent workforce and while we are downsizing in London we are reinvesting in other UK hubs," she added.

RBS, which is more than 70 percent state-owned, is in the midst of a major restructuring aimed at returning the bank to profit after almost a decade of losses. In its 2016 annual report the bank revealed its global workforce has shrunk from around 226,000 in 2007 to around 77,000.

Earlier this month, the Edinburgh-based lender, rescued in a 45.5 billion pound ($59.8 billion) bailout at the height of the financial crisis, beat first-half profit forecasts, showing signs a long-promised recovery is finally gathering momentum.

BRITISH CUTS

RBS has cut around 2,000 staff across Britain so far this year excluding Unite's latest figures, amounting to around 3.5 percent of its 57,000 staff in the country as of December 2016.

"RBS's fixation with cutting employee numbers, restructuring and offshoring work that could reasonably be done by displaced staff within the RBS IT community is unacceptable," Rob MacGregor, Unite national officer, said on Tuesday.

"Unite is angry that the massive scale of IT job losses will sap morale, productivity and faith in the company."

Most layoffs have been in its branch network, where the bank had announced plans in 2016 to cut about one in every 10 jobs.

In March, the lender said it planned to close about 180 bank branches in Britain and Ireland and about 1,000 roles were at risk in the latest round of cuts and closures.

RBS has also announced several rounds of job cuts earlier this year, with plans in June to cut 443 jobs dealing with business loans, many of them moving to India.

In May, the bank said it was eliminating 154 contractor roles and making an additional net 92 job cuts in an overhaul of its back office operations.

(Additional reporting by Sanjeeban Sarkar in Bengaluru; editing by Greg Mahlich and Alexander Smith)

By Anjuli Davies