Security measures for the London 2012 Olympic Games – which could include crash barriers and security fencing – is set to cost £757 million, it has been reported.

According to the Telegraph, the revised figures are up from the previous figure of £600 million and way beyond a readjusted £450 million.

But the government is warning that dissident Republicanism is a real threat to the Games.

Hugh Robertson, the minister for sport, was quoted by the newspaper as saying: "The security situation is uncertain.

"When we started talking about this two years out, nobody foresaw, for example, the rise in the threat of dissident Republicanism that they're facing over the water in Ireland."

To that end, an extra £363 million has also been reserved if a major security incident happens at the Games.

Last year, the Home Office announced that part of the cash given to the London Organising Committee (LOCOG) would go to installing security fencing and carrying out bag searches at Games venues across the UK.ADNFCR-3337-ID-800409549-ADNFCR