Tens of thousands of workers in the UK are going without basic access to toilet facilities in the workplace, one of the UK’s biggest unions has found.

Unite, which represents nearly 1.3 million workers in the UK, said it found evidence of staff at big branches of high street banks urinating in buckets, while some building sites did not have female toilet facilities.

Bus drivers denied toilet breaks for five hours, and call centre workers made to log out and back in to go to the toilet are among thousands who are having access to toilet facilities restricted.

The union is calling for employers to take action after it said affected workers are suffering a “deeply humiliating” lack of toilet dignity.

Those worst affected were in industries including construction, bus and lorry driving, agriculture, warehousing and banking and finance.

It follows a “period dignity” campaign earlier this year by Unite, which highlighted the disadvantage faced by women without decent access to sanitary facilities.

The union also warned that restrictions or lack of facilities could worsen the health conditions faced by some workers, adding that employers were continuing to breach health, safety and welfare duties.

The calls coincide with World Toilet Day on Monday, which aims to raise awareness of the 4.5 billion people worldwide who live without access to a safe toilet.

Gail Cartmail, assistant general secretary, said: “It is clearly deeply humiliating for the workers who are being denied toilet dignity. Employers have got absolutely no excise for ensuring toilet dignity and if they fail to do so they should be prosecuted by the Health and Safety Executive.

“Unite will not be passive on this issue, if the workers are denied toile dignity we will name and shame the guilty parties.”