WHAT happens when workers live in fear and are denied a collective voice was made painfully clear to me in Qatar.

Our beautiful game that is football is being stained by the blood and misery of hundreds of thousands of workers who are treated no better than slaves.

Travelling to Qatar as part of a Unite-Building and Wood Workers’ International delegation, accompanied by Labour MPs Naz Shah and Ian Lavery, what I witnessed and heard shames Fifa as well as the rulers of the Gulf monarchy awarded the 2022 World Cup.

It is a human tragedy and together we must unite to demand fairness and decency for the legions of abused migrants on whose broken backs the football tournament will be built. Men and women who have been plunged deep into debt to buy their way to Qatar on the promise of higher earnings and tolerable accommodation to build the “greatest show” on Earth.

People who when they arrive in the fabulously wealthy Middle Eastern state are frequently short-changed, cheated of agreed wages and expected to scrape by on a pittance. Workers who, as I saw, are packed eight or 10 to a room in squalid, unsanitary labour camps for years on end when the law stipulates a maximum four beds.

Grafters who have their passports removed so they become prisoners of employers, trapped in Qatar unless unscrupulous bosses issue them permission to leave under the detested kafala system.

These people are literally worked to death in searing heat, which tops 50°C in the summer, with the authorities quick to claim they die from natural causes, often a heart attack, to avoid responsibility and compensation.

It makes my blood boil to know this is happening amid the opulence of the planet’s richest country per head. The workers constructing the World Cup infrastructure — the roads, hotels, shopping centres and offices as well as the stadiums — deserve to be treated with respect.

That’s why Unite and other organisations, in Britain and across the world, will do everything in our power to improve conditions. We will demand that candidates for the Fifa presidency tell the world what they would do to stamp out these abuses. We will demand too that our own government and the Football Association get on board and use their influence to ensure there is no hiding place for the guilty, or the perpetrators of such inhumanity.

Because it doesn’t have to be like this: wages could be higher, accommodation better, health and safety improved and workers free to organise collectively and move freely. On the delegation, we saw the good as well as the bad. If a minority of companies can treat workers as human beings and still make a profit, then the shameful majority have no excuse.

Qatar is scarred by enemies we also encounter in Britain — hostility to trade unions and a construction industry washing its hands of responsibility by subcontracting work.

Construction is still the most dangerous occupation in Britain, but advances fought for by this movement keep workers safer and stop companies cutting corners. Day in, day out, we fight to hold on to the basic health and safety provision we have in this country. But we also owe it to our fellow workers to fight for these protections for them.

We must stand firm here and say to Qatar if it’s to be worth the 2022 World Cup the desert kingdom must raise its game. Or Fifa must strip the tournament from a land where the dead workers already outnumber the players who would kick a football in six years’ time.

• Len McCluskey is general secretary of Unite.