Serco wants to move its staff to monthly pay, which will force low-paid workers to stretch a week's wages across a month, increasing the risk of debt and missed bills, says Unison.

The union says that cleaners, porters, caterers and others at NHS Forth Valley are already struggling to make ends meet and could face increased financial hardship if Serco implements the change.

Unison NHS Forth Valley branch secretary, Karren Morrison, said: ‘We are doing everything we can to find a solution, but we still have no guarantees that Serco are listening to low-paid NHS staff. 

‘Staff do not want to go get into debt for a change they never asked for. These are low-paid cleaners, porters, caterers who are already struggling to make ends. It's unfair to put them through this stress and anxiety.

‘There is still time for Serco and NHS Forth Valley get around a table with us to find a solution.'

In response, a Serco spokesman, said: ‘We are disappointed that Unison members are balloting for strike action. Our discussions with colleagues and trade unions remain ongoing and we are listening to all feedback received.

‘No final decisions have been made whilst consultation meetings are ongoing. We continue to help colleagues understand the proposed change and offer support for any transition period agreed. Our trade unions are regularly updated.'