Olympic infrastructure not to blame for projected £2bn overspend, MPs say

However, the Public Accounts Committee warned that the running costs of the event, particularly in relation to security, were already £2 billion over budget.

Committee chair Margaret Hodge said that the London 2012 Organising Committee (LOCOG) needed more than twice the number of security guards it originally estimated. The full cost to the public of the event and its legacy projects was heading for around £11bn against a Public Sector Funding Package of £9.3bn, she said.

"It is staggering that the original estimates were so wrong, LOCOG has had to renegotiate its contract with G4S for venue security from a weak negotiation position and there is a big question mark over whether it secured a good deal for the taxpayer," she said.

"Given the scale of costs outside the funding package, what we need within six months of the end of the Olympics is a single auditable account covering the total costs to the public of the Games and their legacy."

The Committee also raised concerns about the lack of clarity on who was accountable to Parliament for delivery of the Games' legacy benefits, including securing future uses for new venues and regeneration plans in the east end of London. A further £450 million has been spent on getting one million more people involved in sport as a result of the Games - however, as only 109,000 more people have taken part in sporting activities since the programme began the Committee said this was "poor value for money".

The Department for Culture, Media and Sport has overall responsibility for delivering the Olympic programme. It works with the Olympic Delivery Authority (ODA), which is responsible for the construction of new venues and infrastructure required for the Games, and LOCOG, which is responsible for staging the Games.

The Committee said that LOCOG was "intended to be privately funded" through sponsorship, merchandising, ticket sales and contributions from the International Olympic Committee. The body had "done well so far" in generating revenue", but needs to raise a further £200m to reach its target,

"The Government is obliged under guarantee to meet any shortfall in LOCOG's budget," the report said.

The Committee was told that responsibility for delivery of the Games' legacy was to be "shared across many different parts of Government", it said.

"This rings alarm bells about the effective integration of the various legacy plans and about clear accountability to us and the taxpayer. When we return to the examination of the Olympic legacy we expect clarity over precisely who will be accountable to parliament for delivering the benefits to taxpayers from their significant spending on this programme," the report said.

DCMS said that certain costs had always been considered outside of the budget including the £766m cost of the land for the Olympic Park and at least £826m to deliver the legacy programme. It said that £100m of the funding package would remain as "headroom".

"With over 140 days to go until the Olympic Games we are on time and under budget, with over £500m worth of uncommitted contingency remaining. We are in a strong position and, while we can't be complacent, are confident that we can deliver the Games under budget," a spokesman said.

He added that the Government had been clear that legacy funding was to come from "existing business-as-usual budgets". "These are for projects designed to capitalise on hosting London 2012 but are not an additional Olympic cost," he said.