The UK civil service is facing a fresh row over public sector pay with just months to go before Brexit talks with the EU begin.

The First Division Association (FDA), representing senior Whitehall officials, and the Public and Commercial Services Union (PCS), representing civil servants, has called on the government to end its pay freeze.

"The civil service is under immense pressure at all levels, particularly in the lower grades that have been disproportionately hit by 110,000 job cuts since 2010," a PCS spokesman told IBTimes UK.

"Everyone is having to do more for less pay so, as well as starting to invest in our public services again, the government must end the pay freeze and we look forward to discussing with FDA and other unions how we can take action together to bring this about."

Public sector workers, including civil servants and NHS workers, have faced a pay freeze since 2010, and then an annual salary rise capped at 1% from 2012.

The former Chancellor George Osborne announced in his 2015 Budget that the cap would stay in place until 2019. The FDA has written to the Senior Salaries Review Body (SSRB), which issues pay recommendations to the government, to call for a hike.

"Fresh from reducing the size of their departments, the SCS is now tasked with implementing Brexit on top of all of the Government's existing priorities," said Dave Penman, the general secretary of the FDA.

"To quote one member, '...the country needs a civil service that is optimistic, energised, proud, confident and ambitious – what we have is a senior civil service that is thoroughly dispirited and demotivated."

A spokesperson for the civil service stressed Whitehall is "fully focused" on delivering the government's commitment to split from the EU.

"We are equipping ourselves with the right people and the right skills across government to make this happen," the spokesperson said.

Theresa May plans to invoke Article 50, the mechanism to leave the EU, by the end of March 2017. The Supreme Court is expected to rule in January whether MPs should vote on the issue.

The prime minister was dealt a blow when Sir Ivan Rogers, the UK's representative to the EU, quit the post. But Sir Tim Barrow, the former political director of the Foreign Office, was drafted in days later to take up the top diplomatic post.