Royal Bank of Scotland (RBS) is set to spend £6bn on IT and marketing over the next five years in an attempt to mitigate inefficiency stemming from integration of acquired businesses.

The bank’s chief executive, Stephen Hester, said the investment would go towards reversing the negative effect of intensive business integrations, overall lack of investment in technology and failure to build a consolidated IT platform.

Hester told delegates at a Bank of America Merrill Lynch conference in London that RBS had previously invested more in disparate systems inherited from acquired businesses, rather than changing the bank.

Meanwhile, the bank’s redundancy programme is under way. Earlier this year, RBS said that around 2,300 UK back-office jobs – which often includes IT workers – would be eliminated.

In a submission to the Scottish Parliament inquiry into the banking crash last week, RBS gave no overall figure for job losses but said that since last October it had identified around 800 redundant roles in Scotland alone.

While admitting the recession came as a "body blow", RBS said the job cuts have not all been progressed and that it is impossible to say how many staff may be redeployed into alternative roles.