Information reported to Action Fraud suggests that the fraudsters operating these companies have managed to infiltrate NHS practices and hospitals as part of training or open days and in lunchtime meeting sessions for staff.

They also advertise their services to staff members and have been known to set up stands in the reception or restaurant areas.

The companies request the person signs forms which give them permission to liaise with HMRC on their behalf, stating their fee will be charged after the rebate is received.

However, HMRC has confirmed cases where the tax authority has issued refunds to the companies in relation to requests received and authorised by the staff member. Once the refund is obtained all contact with the companies is broken and the victim of the scam does not receive their rebate.

Action Fraud reports instances of similar types of tax rebate fraud has also affected police officers, airline staff and teachers. It recommends that anyone approached in this way should do research online to ensure the company is reputable by checking the registration details are correct and by viewing feedback online.

It also cautions against responding to unsolicited emails, texts or calls offering rebate services and says individuals should make sure they are aware of and agree to any commission that will be paid to a rebate company prior to signing any documents.

Action Fraud has not provided details of the nature of the tax rebate, but a number of companies have been advertising their services in connection with claims for uniform maintenance, cleaning and repair costs, which are tax deductible.