Matthew Taylor said his report on the gig economy - covering such firms as Deliveroo, Uber and Sports Direct - is due out "in a couple of weeks" Daniel Leal-Olivas/AFP

The author of an eagerly awaited report into employment practices poured cold water on union hopes he will crackdown on the gig economy.

Matthew Taylor told a TUC conference that up to three out of four workers wanted these flexible arrangements and changing that was the "last thing we should do".

Taylor said he hopes his report, which he says is a couple of weeks away from publication, will instead make it easier to argue about the importance of the quality of work and flexibility in the modern jobs market.

Taylor told the audience of union officials and campaign groups in London that the UK's flexibility job market was a feature other countries envied.

The government appointed the former advisor to previous Prime Minister Tony Blair last year, amid growing union anger at the increase in zero-hours working and the growth of self-employment contracts at such firms as Sports Direct, Deliveroo and Uber.

But Taylor's speech came on the same day that the TUC launched a report slamming gig economy, saying over three million people – one in ten of the UK workforce – now faced insecurity at work.

The union added: "Not only do they often face uncertainty about their working hours, they also miss out on rights and protections that many of us take for granted, including being able to return to the same job after having a baby, or the right to sick pay when they cannot work."

The TUC estimates the gig economy costs the taxpayer £4bn ($5.1bn) a year in lost tax and higher benefits.

"I am personally shocked about how technology is used as a tyrant in the workplace" TUC general Secretary Frances O'Grady told The Observer at the weekend.

"Tracking people going to the toilet. Tracking the work they do. All of that feels Dickensian in its failure to respect workers as human beings. They are just commodities. There is something really sickening about it."