A new visa scheme to reduce staffing shortages in the sector has left many open to exploitation, an investigation by the Observer has uncovered.

Some overseas workers are being charged thousands of pounds in illegal fees by agencies supplying carers to homes and home care agencies, while working to pay off their debts under exploitative conditions, according to the findings.

By law, agents cannot charge a fee for trying to find or finding work for a candidate. The practise of charging recruitment fees is considered a human rights abuse which leaves workers vulnerable to exploitation and was previously exposed in the UAE and Qatar.

However, the fees are often listed as a “processing”, “service” or “admin” charge, and the breakdown of fees or full amount is not fully disclosed until the worker has reached the UK when they have already paid for relocation and flights, the investigation has found.

The investigation has uncovered fees ranging from £3,000 to £18,000 charged to workers from India, the Philippines, Ghana and Zimbabwe, with some trapped in debt bondage due to these fees.

Some have become trapped in debt bondage – a form of modern slavery – as a result of the fees. Suspected victims described how agents had deducted money from their salaries and withheld their passport or residence permits until they repaid the sum owed.

Others claim to have been subject to abuse and threats or paid less than the minimum wage. They cannot speak up because the sponsorship system for care workers means their visa is tied to their employer.

The Department of Health responded in a statement that reports of illegal employment practices in the sector are taken “very seriously”, and that those found operating unlawfully could face prosecution, adding that providers must comply with ethical standards laid out in its code of practice for international recruitment, which bans recruitment fees and says any costs incurred by agencies must be charged to employers.