ast week’s Budget displayed the fruits of the Government’s fiscal conservatism: the private sector is growing, employment is at an all-time high and the recovery is strong. Now will come a debate about spending priorities. A significant body of opinion argues that defence should be a major area of interest for the next government. The world, after all, is highly unstable. The last few days have seen a horrific attack on a museum in Tunisia – a symbolic assault upon the cultural centre of a fragile democracy. Islamic State wreaks havoc in the Arab world. And Russia continues to gobble up parts of Ukraine.

The lesson of previous conflicts is not that a country can spend less by preparing for the variety of limited warfare that it would feel most comfortable fighting, but that it has to be prepared for anything and everything. Britain could not have predicted the Argentine invasion of the Falklands or Saddam Hussein’s invasion of Kuwait. It has, however, made certain security commitments in the 21st century, and some Conservatives MPs argue that this means sticking to the Nato ambition of spending at least two per cent of the GDP on defence. Owen Paterson, a former Cabinet member and respected figure on the Tory Right, will make a robust case for better preparedness in a speech later this week. Michael Fallon, the Defence Secretary, has told this newspaper that he will fight hard to ensure that Britain makes an appropriate contribution to Western security. Fault lines for debate within the Conservative Party are obviously opening up.

Some will say that with the economy growing, a percentage target for UK spending on defence is unnecessary: two per cent in 2015 is worth more than it would have been in 2010. And some members of Nato not only fall well short of two per cent but actually short of one per cent. Nevertheless, the Western alliance has to honour its obligations and Britain’s political leaders should make an unequivocal commitment to meeting the two per cent target. Shaving a little money off the appropriate spend on defence is a false economy. The price for upholding freedom is one worth paying.