There are calls for the Exeter marine who was convicted of making bombs for terrorists, to be given a harsher sentence.
Taunton-based Ciaran Maxwell was jailed for 18 years after stockpiling stolen weapons intended for illegal use by dissident Irish republicans.
In a letter to the Attorney General, former Armed Forces Minister Mike Penning says Maxwell could be released in six years, something he says "cannot be allowed to happen."
Ciaran Maxwell, 31, stashed anti-personnel mines, mortars, ammunition and 14 pipe bombs - four of which were deployed - in purpose-built hides in Northern Ireland and Devon.
He had been smuggling arms out of his base near Taunton, and stashing them in purpose built-hideouts, 19 of which were in Devon, for over five years.
The judge eventually sentenced Maxwell at the Old Bailey to 18 years in prison for his crimes, stating that he had no doubt that he was a "dangerous individual" who took pleasure in his bomb-making abilities, and dispelled claims that he had no strong Republican sympathies.
The Ministry of Defence says a review of security procedures in military bases was carried out in the wake of Maxwell's arrest.