Boris Johnson and Michael Gove have centred the Brexit debate on immigration this morning by slamming Prime Minister David Cameron's record on net migration in a letter to the Sunday Times.
Shifting the spotlight from economists, who have generally sided with the 'Remain' camp thus far, Johnson and Gove said Cameron's failure to curb net migration, a manifesto pledge, was "corrosive of public trust".
They added: "Voters were promised repeatedly at elections that net migration could be cut to tens of thousands.
"This promise is plainly not achievable as long as the UK is a member of the EU and the failure to keep it is corrosive of public trust in politics."
The letter follows the news that net migration to the UK has risen to 333,000, the second highest figure on record.
And – in case you've missed it – Boris and Gove reminded everyone that such high migration is unsustainable, and said they were "particularly concerned about the impact of free movement in the future on public services."
They go on to attack Cameron's poor negotiation with the EU before the referendum campaigns started in earnest.
The letter, co-signed by Labour MP Gisela Stuart, said: "It's government policy that 'EU migrants should have a job offer before they come here'. But the EU did not agree to letting the UK implement that policy during the renegotiation of our membership."
Number 10 dismissed the letter as a distraction from the economic issues that, so far, have played out well for the remain camp.
In a statement, Number 10 said: "This is a transparent attempt to distract from the fact that the overwhelming majority of economists and businesses are clear that leaving the single market would be disastrous for jobs, prices, and opportunities for working people."