Labour has called upon the government to provide a £1m research fund for charities to develop policy on the long-term mental health effects of the wars in Iraq and Afghanistan.

The call has gained support from veterans’ charity the Royal British Legion, whose research estimates that by 2020 1.8 million people in the armed forces community will be living with a long-standing illness.

Mental health issues are often a delayed reaction to serving in the armed forces, said a spokesperson for the charity, stating that post-traumatic stress disorder takes an average of 13 years to become evident.

Shadow defence secretary Jim Murphy is leading the call for the fund, which would be open for relevant charities to bid for funds to develop long-term policy research, and would in turn translate into policy adopted by the government.

“We must prevent an epidemic of invisible injury,” said Murphy. “With thousands having experience of Iraq and Afghanistan legacy issues are more important than ever… Charities must be enabled to work on the solutions which are currently lacking.”

Labour says if it were in power it would find the funding by readdressing the service personnel cuts which under the current government are facilitated on a “broad proportion” basis, it says. Instead it would top-slice the number of one-star generals (senior commanders) in the services, which it says are “top heavy”. The move would save tens of millions of pounds, the party claims, of which £1m would go towards the legacy fund.

“We have more admirals than ships; proportionately we have more officers in our forces than our international counterparts; the number of one-stars has risen by a third since 1990,” the party claims.

A spokesperson for the Royal British Legion said: "For many of our brave armed forces, their injuries - both visible and invisible - will have a lifelong impact. As a nation, we must prepare to support them now, whilst the sacrifices our services personnel are making are at the forefront of the public's mind...We therefore welcome this debate and call on all parties to work together on constructive solutions."

At the time of publication, the Ministry of Defence was unavailable to comment on how it would respond.