Sir Alan Sugar’s property company Amsprop Estates is set to buy IBM’s office on London’s South Bank.

Amsprop is thought to be paying around £115m for the office on 76-78 Upper Ground, SE1.

The 217,000 sq ft (20,159 sq m) building is owned by the founders of the River Island clothing chain – through the family’s company, the Lewis Trust.

The acquisition is the first for Amsprop since Steven Lewis joined from Burford as an executive director to lead its expansion.

The Lewis Trust’s property company, UK & European Investments, bought the building in 2003 from Land Securities for £74.5m.

The building represents development opportunity when IBM lease runs out in 2014.

Lewis Ellis is advising UK & European and BH2 is advising Amsprop.