The defence spending and security review will result in cuts of at least 25% in the numbers of lawyers in the Army and Royal Air Force, the Gazette understands.

The cuts will include lawyers who advise frontline troops and commanders on compliance with the Geneva Conventions in Afghanistan.

An informed Gazette source said that all ranks of lawyer in the Army Legal Services (ALS) and Directorate of Legal Services RAF (DLSRAF) can expect cuts through natural wastage and enforced job losses, including the senior ranks of brigadier, air commodore, colonel and group captain.

There are around 120 lawyers in the ALS, three-quarters of whom are solicitors, and 35 solicitors in the DLSRAF.

Eight ALS lawyers are in the Afghan theatre at any one time, advising on compliance with the conventions and making initial reports on disciplinary cases. Army commanders at every level have access to legal advice from ALS officers who, in the words of the army website, ‘are at the heart of the command and are often asked advice on the most sensitive issues’.

The current expectation is that these ALS lawyers spend six months in Afghanistan, then return to the UK for six months in rotation. The full complement of ALS lawyers with the relevant expertise to cover operations in Afghanistan is therefore at least 16, but this capacity has not been ringfenced.

A Gazette source said there is concern within the ALS that a reduction in the number of lawyers engaged with operational matters will mean the service is ‘running that little bit hotter’.

Khawar Qureshi QC, a barrister specialising in international law, said cuts in operational advice would carry a risk. ‘Many would accept that public spending cuts are needed,’ he said. ‘But if cuts come in this area, there is an attendant risk which must be carefully assessed.’

Qureshi said the UK has an obligation to ensure compliance with the Geneva Conventions. He said: ‘Soldiers on patrol in Afghanistan and other conflict zones may need real-time guidance and their actions may need to be rapidly assessed for compliance with convention obligations.’

The MoD did not provide a comment.