Unions have cautioned employers against penalising staff who have been stranded overseas because of the erupting Icelandic volcano.

TUC general secretary Brendan Barber called on employers to be sympathetic to the plight of their employees and flexible in their approach to resolving the situation, such as by allowing them to extend their leave, or use leave days from the following year.

Teaching unions have warned that local authorities may be vulnerable to a legal challenge for unlawful deduction of salary if they dock the pay of teaching staff unable to return to work.

The Employment Rights Act 1996 Part II (ERA 1996 s.13 to ERA 1996 s.27) makes it unlawful for an employer to make any deduction from the wages of a worker unless the worker has agreed in writing to the deduction being made or it is required by law (eg deductions for PAYE and national insurance).

So if an employer reduces or fails to pay wages without the employee’s consent it may amount to an unlawful deduction from wages, even if the employee owes money to the employer. In other words, employers are not entitled to take the law into their own hands.

However, this does not prevent an employer from recovering money that has been overpaid, or not paying wages which have not been earned – because an employee has failed to turn up for work – if the employer’s policy on this is set out as part of the employment contract.

Employees have a duty to report for work (other than for reasons that their contract specifies they will get paid time off for, such as sickness or maternity leave). Employers should have a policy in place which sets out, both in terms of contractual and statutory rights and obligations, how circumstances which prevent or make it difficult for employees to get to work will be dealt with.

Such a policy might advise that failure to report for work will be classed as unpaid leave if holiday cannot be taken.

Whether employees can be granted additional time off depends on their employment contracts as there is no entitlement in statute.