The protest, organised by GMB Union, was sparked by the BMA's decision to insource its employment and support staff advisors, and treat them as day one employees.

The move has resulted in the 44 members of staff - who are the first port of call for BMA members seeking help – being placed on the lowest pay band for their grade, regardless of how long they have worked on behalf of the union.

GMB says its members have unanimously rejected an offer from the BMA - worth around £400 in-year before tax - because it did not resolve the issue at the centre of this dispute.

A recent consultative ballot of affected members saw 91% indicate their willingness to strike if necessary.

Gavin Davies, GMB senior organiser, said: ‘These staff have worked tirelessly on behalf of BMA members.

‘All we are asking is for the BMA to do the right thing and recognise their years of service.'

In response, a BMA spokesperson, said: ‘We have worked closely with the GMB to find a way ahead in this dispute, raised on behalf of 44 colleagues, whilst balancing our obligations to all our 570 staff at the BMA.'

The added: ‘We have met and gone above and beyond our TUPE obligations during the transfer of these colleagues and we remain committed to supporting fair and beneficial terms for all colleagues at the BMA.

‘We will now be moving to Acas-mediated discussions with the GMB and will be fully engaging in the process.'