Labour disputes are nothing new to the Gulf construction market, but the recent wave of unrest appears to mark a new and worrying chapter. Not only have they been violent, with extensive damage done to property and hundreds of arrests made, they have also hit the construction sites of some of the leading contractors in the field.

'You are not talking about some second or third tier contractor, which does not pay its workers for months or provides them with squalid accommodation,' says an Abu Dhabi-based contractor. 'This is Laing and CCC, who are viewed, by the market at least, as some of the best employers in terms of payment and accommodation.'

Money and living conditions remain at the heart of most labour disputes. In Laing's case, the catalyst was reported to be a cut in overtime payments. As for Al-Ahmadiah, its problems began after a more formal clocking-in system was introduced, leading workers to believe their pay packets would be docked. But other more bizarre factors can come into play, as was highlighted by the 1,000-worker rampage at CCC's camp in Qatar.

'This event followed the death of a Nepali worker, who passed away in his sleep of natural causes,' the Ras Laffan City (RLC) management said in a statement issued on 17 April. 'Unfortunately, his fellow workers wrongly perceived the death of their colleague to be of non-natural causes and the workers were alleging that the accommodation was haunted.'

Those involved in the subsequent Ras Laffan investigation stand by the official explanation. 'I know it sounds crazy, but the ghost theory is the most plausible,' says one source. 'You have to remember that in camps such as the ones at Ras Laffan you have thousands and thousands of workers from very different cultures, many of whom have never left their village before coming to the Gulf to work. Once rumours start, they spread like wildfire.'

The need for ever greater numbers of labourers CCC alone now has more than 15,000 at Ras Laffan has forced contractors to expand their recruitment drives. To the traditional labour pools of the Indian subcontinent and the Philippines have been added Nepal and China. The greater nationality mix has itself fuelled tension on some labour camps. Last November, Dubai-based Arabtec Construction decided to relocate a group of Nepali labourers away from their Indian counterparts after a fight broke out in which one worker was killed.

Some contractors argue that the number of actual labour incidents has not noticeably changed over the past two years: it's simply that the local media is reporting them more. In the UAE, it is certainly true that barely a day passes without another labour dispute being reported in the English-language newspapers.

The international media has also been taking greater interest, especially since late March, when New York-based Human Rights Watch (HRW) issued a damning report on the treatment of migrant workers in the UAE. 'One of the world's largest construction booms is feeding off workers in Dubai, but they are treated as less than human,' says Sarah Leah Whitson, Middle East & North Africa director of HRW. 'It's no surprise that some workers have started rioting in protest. What's surprising is that the government of the UAE is doing nothing to solve the problem . If it doesn't start taking steps to improve conditions, further unrest seems inevitable.'

The UAE's reaction was swift. Within hours