Votes cast by troops serving overseas may not be counted for May’s elections, Labour claimed tonight.
The ballots watchdog wrote to the Government last November suggesting a shake-up which would make it easier for soldiers posted abroad to exercise their democratic right.
But Labour claimed ministers have failed to act on advice.
The row unfolded after Veterans Minister Johnny Mercer suggested an overhaul was up to the elections regulator.
Answering a written parliamentary question, he told MPs: “The Ministry of Defence will continue to work with the Electoral Commission to ensure that overseas Armed Forces votes are processed quickly.
“However, current parliamentary rules regarding the timescales placed on postal voting are outside the remit of the MoD.
“Additionally, the introduction of any alternative voting processes for overseas voters remains a matter for the Electoral Commission to consider.”
But the Commission’s director of electoral administration and guidance, Ailsa Irvine, hit back in a letter, telling Mr Mercer: “Any changes relating to overseas service electors, including related deadlines and changes to voting processes, would require changes in legislation.
“We have recommended that the Government consider innovative new approaches to improving access to the voting process for electors who are overseas, such as by introducing the ability to download and print postal ballot papers.
“However, while the Commission has this important role in providing advice, it would be for the Government to bring forward the necessary legislation to enable such changes.”
The watchdog “will in any case continue to work with the Ministry of Defence and others to provide information to service voters to help them cast their vote successfully”, Ms Irvine said.
She highlighted “targeted advertising campaigns” before polling day and advice to town halls “recommending that overseas addresses are prioritised when sending out postal ballot packs”.
She added: “We provide specific guidance for members of the Armed Forces on our website on how to register and vote.”
Labour warned that denying troops votes which would be counted would break the Armed Forces Covenant.
Shadow Defence Minister Stephen Morgan said: “With important elections fast approaching, I am deeply concerned by the challenges of overseas personnel postal votes being both delivered on time and, crucially, counted in UK elections.
“What worries me further still is the Electoral Commission’s advice to help remedy this problem has been ignored by Government, whilst personnel being unable to vote in UK elections would also be in breach of the Armed Forces Covenant.
“This is an urgent matter that must be resolved quickly to ensure our servicemen and women can exercise their democratic right to vote, just as any other UK citizen.”
A Government spokeswoman said: “Postal votes for overseas personnel are prioritised by Royal Mail and the British Forces Post Office.
“But, as with every election, we strongly advise personnel to consider appointing a proxy voter, due to the challenges with international delivery over long distances.”