The Court of Appeal will next month consider an appeal against a ruling that has left care charities facing an estimated £400m back-pay bill for sleep-in carers.
The membership umbrella body Care England said today that it had been granted the right to intervene in the case, which is being brought by the learning disability charity Mencap against a judgment by the Employment Appeal Tribunal.
Care England will argue that workers typically spend only a tiny fraction of sleep-in shifts actually working.
The original judgment was one of two that led the government to change its guidance on sleep-in care workers and left care charities facing a back-pay bill for six years’ of arrears, which Mencap estimated would total £400m.
Charities that used sleep-in carers had previously typically paid a flat rate of between £35 and £45, plus an hourly rate for any time spent providing care rather than being asleep. But the revised guidance said the carers should be entitled to the minimum wage for the entirety of their shifts.
The government last year asked charities that owed arrears to sign up to a scheme that gave them 15 months to pay off any arrears.
Mencap says it would owe £20m in back-pay. It has also said that it might have to close 200 residential care homes and other services and make 4,000 staff redundant if forced to pay. Charities signing up to the scheme could effectively be "writing their own suicide notes", it said at the time.
Should Mencap be successful in the Court of Appeal case, which is due to be held on 20 and 21 March, the whole question of back pay would be brought into question.
Martin Green, chief executive of Care England, which has 160 members, said that if the original ruling was upheld there would be "profound effects on the viability of residential domiciliary and supported care".
There are also fears that the ruling could be extended to cover live-in carers.
Matthew Wort, a partner at Anthony Collins Solicitors, which is representing Care England, said: "Surveys have shown that, in practice, on average only 1 per cent of time on sleep-in-shifts is spent working.
"The intervention by Care England introduces other arguments that have not been considered in the case to date.
"The intention of parliament with the introduction of the National Minimum Wage Regulations was always that people carrying out sleep-ins would be paid only when they were awake and working. We are hopeful that the Court of Appeal will be persuaded to interpret the legislation in that way."