Medical secretaries across the NHS could resort to industrial action as anger deepens over their continuing grading dispute.

Staff at Cumberland Infirmary in Carlisle have already voted 'overwhelmingly' in favour of a four-week campaign, culminating in a three-day strike.

And secretaries at Lanarkshire Acute trust and North Glasgow University Hospital trust have also agreed to hold a ballot on possible industrial action.

The unrest in Cumbria was due to start this week and would see secretaries refusing to answer phones, or to transfer patient notes between departments. The following three weeks will see one, two and three-day strikes respectively.

Unison's Cumbria regional secretary Peter Doyle said: 'The staff are determined not to let this drop'.

He said similar campaigns were being prepared by medical secretaries in south Cumbria and in Lancaster. The union claims the specialised work they are carrying out should be rewarded with improved grading. It is currently requesting that they should move from grade three to grade four.

Ann Rhodes, chair of the British Society of Medical Secretaries, said: 'Industrial action will spread - there is no doubt about it - unless the issues are resolved by trusts across the country. There is a lot of frustration and anger around because there are people who are holding entire departments together, yet this has never been recognised in the career structure. '

Both Lanarkshire Acute trust and North Glasgow University Hospital trust have said their hands are tied when discussing pay and conditions because of Whitley Council terms and conditions, which are applied nationally in the NHS.

In a statement, North Glasgow University Hospital trust said: 'We are aware of the concerns of a number of medical secretaries around the grade of their post and we have given an undertaking to consider these grievances on an individual basis. '

Appeal panels would be set up which would take a maximum of eight weeks to make decisions.

Lanarkshire Acute trust also said systems were in place for staff members to discuss their grading and pay on an individual basis. But a spokesman said it was yet to receive any formal notification from Unison about the planned ballot on industrial action.

Jim Devine from Unison Scotland said that the issue should be resolved on a national level by the Scottish Parliament.

'These staff are the forgotten army of the NHS, ' he said. 'They provide a crucial service without which the NHS would collapse. '