With a London 2012 commissioner resigning from her involvement in the Olympic Games over moral concerns about a sponsor, International Business Times UK turns the spotlight on some of the other companies with ethical question marks.

Meredith Alexander, head of policy at the charity Action Aid, sat on the Commission for a Sustainable London 2012, a watchdog for the Games, including human rights issues.

She gave up her unpaid post in protest over Dow Chemicals' sponsorship of the Olympic Stadium wrap, because of its ties with Union Carbide, the company responsible for the 1984 Bhopal disaster.

A gas leak at the company's pesticide plant in the Indian town of Bhopal is estimated to have claimed 25,000 lives, while hundreds of thousands of people have suffered from the disaster, including birth defects and illnesses.

In 1989 Union Carbide paid out $470m (£300m) to the victims in a vast settlement.

What about the others offering cash for the games?

Oil giant BP is listed as a London 2012 partner.

In its most recent controversy, an oil spill in the Gulf of Mexico in 2010 caused an environmental disaster, in which marine wildlife was damaged on an unprecedented scale.

An underwater pipeline initially burst, causing an explosion in which 11 people were killed. Following the incident, oil leaked for three months as BP struggled to gain control of the situation.

BP's "poor management" was partially to blame for the disaster, according to the US government.

As a company, it has been criticised for environmental damage, fraud and dealings with countries notorious for human rights abuses, like Azerbaijan.

British bank Lloyds TSB, a heavy investor in the arms trade, has also given cash to the Olympics.

A 2008 report by charity War on Want revealed that Lloyds held £717.5m worth of shares in the UK arms industry.

It is the principal banker for the defence company BAE Systems, which has sold equipment to despots around the world, including Zimbabwe's Robert Mugabe and Chile's Augusto Pinochet.

As a result of the UK government having had to step in and bail out Lloyds during the financial crisis, it now has a 41 percent stake in the bank. This raises the question why a taxpayer-funded bank is putting sponsorship money into the Olympics, which already has masses of taxpayer cash?

The acccountancy firm Deloitte has also put its name to London 2012.

Deloitte works as administrators for many ailing companies, one of which was the ill-fated Woolworths.

Private Eye revealed that at the time Deloitte had advised Woolworths' bankers to put the company into administration and reject a plan by the department store's management to save the business.

Deloitte then won the £9m administration contract and sacked 30,000 members of Woolworths' staff, without redundancy.

In a recent court battle, a group of the redundant staff won £67.8m in compensation after claiming Deloitte did not consult with unions, as it was legally bound to do, before cutting staff.

As a result of this oversight by Deloitte, the taxpayer will now foot the bill for the compensation payout.

Atos, which is backing the Olympics, is a company with a £100m government contract to carry out medical assessments to see if someone is entitled to disability benefit.

While the final decision on entitlement rests with the Department for Work and Pensions, Atos has been criticised for its assessments, which are carried out by healthcare professionals, for being over-strict.

In one example, Atos ruled a critically ill man as "fit to work" - but he died from his illness three months later.

In addition to these companies, other sponsors include corporations such as Coca-Cola and McDonald's.

A spokesperson for the organisers would not say how much each sponsor is contributing to the Games, claiming it is a private matter that is up to the sponsors to reveal.