"Send in the army".
That familiar bedfellow of "something must be done" can now be heard coming from the mouths of British politicians and commentators.
They offer it as a solution to the Calais migrant crisis that's been disrupting links between France and Britain for weeks incommoding commerce and tourism alike.
Apart from the fact England lost control of Calais in the sixteenth century and it is now part of sovereign French territory, the proposal that British troops be sent to France to secure the Ferry and Eurotunnel terminals and prevent the thousands of migrants there from attempting to stow away on lorries or get through the Channel Tunnel is not a solution.
As things stand London is struggling to convince that it is on top of the situation.
But the pressure Cameron is under is partly of his own making.
His government has failed to keep its - arguably unrealistic - promise five years ago to cut net immigration to under 100,000 a year, so any sense that migration is "out of control" leads to loud headlines and the need to appear to take decisive action.
This means things that are done like providing money for improved fencing at Calais and the offer of sniffer dogs - which make sense - appear inadequate in the eyes of critics.
Clearly, there is an immediate need.
Migrants who have gathered at makeshift camps near the French port after having made their way - in most cases - from the Middle East and Africa via south and south-east Europe need to be given accommodation and have their claims for asylum processed.
This will almost certainly require large-scale police action, where, if France agrees, British officers can help to move the migrants to alternative sites.
But this is not something military forces should be used - or indeed are trained - for.
Beyond dealing with the immediate problem though, the crisis will not be solved until a few other things are sorted out.
EU countries need to start actually cooperating, rather than merely promising to cooperate, in dealing with the thousands of desperate people crossing the Mediterranean.
Italy and Greece - and now increasingly Hungary - where most of the Syrians, Iraqis, Afghans, Eritreans, Sudanese and others first arrive in the EU can't cope on their own.
EU leaders - with the exception of the Brits, Danes and Hungarians - agreed at their June summit to share the burden by accepting allocations of asylum seekers, but progress is clearly not fast enough to keep up with the numbers arriving.
And while not all the migrants are refugees from conflict and oppression, Britain and its EU partners have a moral and legal obligation to give asylum claims a fair hearing.
The EU could also help to reduce the number of purely economic migrants by getting serious about helping African and Middle Eastern countries provide jobs and decent living standards by opening up their markets and investing in those countries, as well as better targeting development aid.
Such a policy was put in place twenty years ago under the Barcelona Process, but it has always seemed to lose out to other political and economic priorities and has proved inadequate.
But that still leaves the main cause driving the current surge in the number of migrants - the conflict in Syria and Iraq and the anarchic situation in Libya.
The UK has defended its parsimony in giving asylum to Syrian refugees by pointing to the humanitarian aid it is giving to help Syrian refugees in the region and the people displaced inside the country.
It is true Britain is one of the largest aid givers, however, it is revealing that newly released figures show the UK spent much more bombing Libya during the revolt against Colonel Gaddafi in 2011 than it did on aid to help stabilise the country after his overthrow.
And it is precisely the failure to stabilise Libya and its further descent into chaos that has enabled migrants to cross the Mediterranean in such large numbers.
The same skewed approach can be seen in Syria and Iraq.
The US alone is spending more than $ 9 million a day on its air strikes on Islamic State forces, while the UN-led relief operations for the millions of refugees who have fled to neighbouring Turkey, Lebanon and Jordan, let alone the millions displaced inside Syria, are chronically underfunded with less then a third of the money needed arriving so far this year.
So is it any wonder people are desperate enough to risk the journey to Europe?
If the politicians in London want to end the crisis in Calais, they don't need to send in the troops, they need to shoulder a fairer share of the burden of asylum seekers in the EU, something they are currently refusing to do.
They also need to find the money to spend more on supporting international relief operations and be ready to invest in the reconstruction of Libya, Syria and Iraq if and when the fighting ends and the circumstances allow.