London: British Prime Minister David Cameron on Monday agreed to double the budget for the London 2012 Olympic and Paralympic ceremonies after he was shown the initial plans.
The Games' security budget has also doubled, a government report out Monday showed, with plans to recruit almost 14,000 extra personnel.
Organisers will now have £81 million ($126.3 million, 94 million euros) to spend on the opening and closing ceremonies, which are expected to be watched by a combined total of four billion global television viewers.
"We decided to go in at the higher figure for the benefit of the country," explained Sports Minister Hugh Robertson.
"We hope it's an impression that people will say 'we want to come back here, do business and spend tourism money'," he added.
Around 20,000 performers are set to take part in the four events, which are expected to net billions in advertising revenue.
Slumdog Millionaire film-maker Danny Boyle has the task of producing the main opening ceremony, although few other details about the shows have emerged.
Early rumours suggest former Beatle Paul McCartney and pop giants Take That will kick off proceedings.
"The equivalent advertising value that will deliver for the UK could be up to £5 billion, however, with regards to perception of London and the UK and a tourism legacy you could say that they will be priceless," said Martin Sorrell, head of advertising giant WPP, on Sunday.
The operation to provide security at more than 100 venues has swollen after the decision was taken to boost staff numbers, the December 2011 Olympic Quarterly Economic Report showed.
The report stressed that the increase was not in response to a specific security threat.
The overall budget for the Games remains at £9.3 billion, with £528 million so far unspent.
The security cost has risen to £553 million, the figures from July to September showed, up £282 million on the 2010 spending review baseline.
Instead of the 10,000 security officers initially planned for, there will now be 23,700, with the majority coming from a private firm. The military and volunteers will make up the rest.
The government and Games organisers have gone through a detailed analysis of the number of security staff needed, Olympics minister Robertson explained.
"As a result, to ensure a safe and secure Games, they have revised the numbers of trained staff required," he said.
"We are therefore investing additional funds in providing nearly 24,000 venue security personnel plus specialist security equipment."
Last month, defence minister Philip Hammond said Britain was prepared to deploy surface-to-air missiles to protect London during the Games, shortly after the government rejected reports of US security fears.
"The government carried out a full review of security arrangements in late 2010 and remains confident the right plans are in place to deliver a safe and secure Games for all," the report out Monday said.
"The government's approach is intelligence-led and risk-based, giving the flexibility to respond to any changes between now and Games time.
"The planning assumption we have used throughout is that the Games will be delivered in the context of a 'severe' level of terrorist threat."
Security has been a key concern for all Games hosts and organisers since the 1972 Olympics in Munich when nine kidnapped Israeli athletes and four of their captors from the Palestinian Black September group, as well as a German policeman, were killed in a gun battle.