A leading figure for the London Olympics has described the job of the procurement team as "one of the biggest challenges of any project in the UK".

In an exclusive interview with SM, John Armitt, chairman of the Olympic Delivery Authority (ODA), said: "There can't be a project which is more in the public spotlight." He said the large number of stakeholders, tight timescale and in some cases "counter productive" public procurement rules made it tough.

Escalating costs have been widely criticised, the original budget of £3.4 billion having risen to more than £9 billion. In April, a Commons committee said a fourfold increase in the budget for the aquatics centre "shows a risible approach to cost control".

Armitt said ODA buyers had been accused on occasion of being held over a barrel by suppliers but could not continue negotiating forever.

☛ Read the full interview by Rebecca Ellinor in 4 September issue. John Armitt will deliver a keynote address at the CIPS Premier Conference in October.