Roughly 8,000 people in Cornwall are potentially having their health put at risk and receiving lower pay by working on zero-hour contracts.

This is according to the South West Trades Union Congress (TUC), which conducted a poll and found that two-thirds of zero-hour workers want to be on permanent and secure contracts.

The TUC has also conducted new analysis that it says shows zero-hour workers are having a tougher time than those in secure employment.

• Nearly a quarter (23 per cent) of zero-hour contracts workers regularly do night shifts, compared to one in ten of the rest of the workforce. The TUC said that night working has been linked to heart disease, shortened life expectancy and higher risk of cancer.

• Zero-hours contract workers are on average paid around a third (£4.10) less an hour than other workers. This is despite 12 per cent of zero-hours workers being supervisors and managers.

• It found one in seven zero-hour workers (16 per cent) did not have work each week, and they work on average 25 hours a week compared to the average of 36 hours a week.

• Not knowing if they would get work next week and being paid low wages was having a "significant impact on mental health" according to union polling.

TUC regional secretary for South West Nigel Costley said: "Too many of Cornwall’s workers have to rely on insecure employment and the worst are zero-hours contracts.

“The vast majority of people on zero-hour contracts want out. The only flexibility offered, is flexibility that works for employers.

“Zero-hour workers regularly work for low pay, including through the night, which puts their health at risk. Many also face the constant uncertainty of not knowing when their next shift will come – adding to their financial struggles.

“We need the government to stamp out these unfair contracts. Working people in Cornwall need solid jobs, with guaranteed hours so they can provide for a decent family life.”

Heart Unions Week, held each year to coincide with Valentine's Day, will be ramping up its campaign for a ban on zero-hours contracts this week with an online petition, with union leaders vowing to negotiate an end to zero-hour contracts in workplaces where they have recognition.