THE biggest social care charity has been criticised for refusing to issue backdated pay to workers who were not paid the minimum wage.

Trade Union Unison says it is furious with the Richmond Fellowship Scotland (RFS) over its treatment of staff who receive a set payment for sleepover shifts.

Unison believe the charity - and many other care organisations across the country - have broken the law by paying workers a flat rate for overnight stays, creating an average pay for some staff below the national minimum wage of £6.50.

The issue is believed to affect thousands of care workers throughout Scotland, taking in almost all staff who do two or more sleepover shifts per week.

Many organisations have now agreed to amend payments and work towards backdating pay for workers for the last five years.

However, while RFS has amended its workers' pay to ensure they receive the minimum, the charity has refused to backdate the money - prompting Unison to raise legal action.

Deborah Dyer, Unison regional organiser for the third sector, said: "We are furious with the Richmond Fellowship Scotland. Refusing to pay staff the minimum wage is a very serious matter, they have left us no choice but to start litigation proceedings.

"Staff at Richmond work incredibly hard providing vital care to some of our most vulnerable people and they deserve decent pay and conditions - and not to be fighting with their employer for their legal right to back pay for non payment of the minimum wage.

"We are still urging Richmond to get back round the table with us to find a solution."

RFS sent a briefing to staff several weeks ago agreeing to pay them the national minimum wage from April 1 under "UK Government guidance".

It follows a decision of the Employment Appeal Tribunal (EAT) in England in 2013 in the case of a carer who tried to claim the National Minimal Wage for all the hours she worked from arriving at her sleepover shift until she finished.

An employment tribunal initially rejected her claim, but the EAT found that where a person's presence at a workplace forms part of their job, the hours spent there should all count as working hours.

Unison claims that while they are in "constructive negotiations" with other organisations over backdated pay, RFS has completely refused to discuss it.

The union has now contacted its members at RFS and is in the process of establishing who is entitled to back pay and how much they are owed before lodging claims at an employment tribunal.

Mike Kirby, Unison's Scottish secretary, said: "We understand the difficulties charities face but you cannot survive with a business model which fails to pay staff the minimum wage.

"This leaves care workers stressed and frustrated, unable to plan their lives, pay their bills or do their job properly. And it means elderly and vulnerable people do not get the service they deserve.

"The Richmond Fellowship has left us with little choice but to deal with this through legal proceedings.

"We hope, even at this late stage, they will get back round the table to find a solution."

A RFS spokeswoman said: "We have led and have been at the forefront of tackling this issue, taking active steps to pay our staff on a new basis.

"We have had little contact from Unison on this issue and do not understand their statement that we are not negotiating and that other charities are.

"Our staff's basic pay is well above the minimum wage and when they are asleep their existing additional allowances are getting further enhanced when required.

This is a key issue that affects all Care and Support Providers in the UK and requires a new funding model to recognise these changes."