Funding for the armed forces should be on a par with the NHS, defence minister Tobias Ellwood has suggested.
Mr Ellwood, the Minister for Defence People and Veterans, said he is "deeply concerned" that Britain is taking its security for granted as the world gets more dangerous.
Amid suggestions the Ministry of Defence faces a black hole of at least £4.9 billion and as much as £20.8 billion over the next decade, the minister said spending on the armed forces must increase.
MPs warned last week that the MoD "simply does not have enough money to buy all the equipment it needs" in a report published by the Public Accounts Committee.
On Tuesday, the US ambassador to London said Britain must consider how it wants to be seen by America and its adversaries while weighing up how it spends its national budget.
Latest figures from the Office for National Statistics show the UK spent 9.8 per cent of GDP on healthcare in 2016.
Mr Ellwood said: "You go back to the 1970s and 1980s and there was a parity between defence spending compared with health and education - and today we have dropped back to 2 per cent.
"The Government often does what people call for. If people call for more money for schools and hospitals, that is often where the money then flows. It is important we raise the profile of the dangers of reducing our defence posture. Once you lose it, you will never get it back.
"I am deeply concerned we have a nation which is fully appreciative of our armed forces but which takes our security for granted."
The former army captain said countries like Russia and China are "rewriting the rule book" and Britain had to ensure it has the "full spectrum of capabilities".