The UK’s Home Secretary, Theresa May, was on Thursday forced to maintain that security plans for London’s Olympic Games will not be compromised, after it emerged that a further 3,500 troops will be needed for the event.

The British military is already supplying 7,500 troops for venue security duties, but London 2012’s security contractor G4S has now stated that it does not have the required levels of trained staff for the event. G4S was originally contracted to supply 13,000 personnel but has stated that only 4,000 are currently working across the Games’ 100 venues, with a further 9,000 still going through the final stages of training, vetting and accreditation.

The move brings the total number of military personnel including reservists protecting London 2012 to 17,000, compared to the 9,500 troops the UK has on tour in Afghanistan. Coming with little over a fortnight until the Games get underway, the latest news serves as an embarrassment to Olympic organisers and proved a hot topic in the House of Commons on Thursday. Labour MP Keith Vaz said: “G4S has let the country down and we have literally had to send in the troops.”

In a statement, Downing Street warned G4S should be held accountable for failing to fulfil its contract – for which it is being paid £284 million. The government is now set to meet the cost of the redeployment of additional troops and May has maintained that London 2012 will deliver a secure Games, adding that the government is confident that venue security costs will remain within the £553 million budget. She said: “I can confirm to the House that there remains no specific security threat to the Games and the threat level remains unchanged. And let me reiterate that there is no question of Olympic security being compromised.”

In other news, the London Legacy Development Corporation (LLDC) has confirmed it received four official bids for legacy usage of the Olympic Stadium by Thursday’s deadline. The announcement will come as a blow to the LLDC, which had extended the bidding process in an effort to attract further interest. The same number of bids for the centrepiece of London’s Games had been received by March’s initial deadline. The number was a significant reduction from the 16 parties that had initially expressed an interest when the tender process was first announced.

London-based radio station LBC reported that newly promoted Premier League football club West Ham United and third tier team Leyton Orient are two of the four bidders to become ‘concessionaires’ of the stadium alongside UK Athletics. An ambitious plan to stage a Formula One race around the Olympic Stadium was last month revealed as one of the four original proposals being considered, along with bids from West Ham, the University of East London/Essex County Cricket Club and the University College of Football Business. However, the University of East London has confirmed that it has now withdrawn from the race. Legacy officials intend to secure a new tenant for the Olympic Stadium by October.