Home Office data released in the final years of the UK’s membership of the EU shows 3,830 migrants were transferred into Britain, while just 1,253 were removed.
The figures appear worse than the now-defunct “one-in, one-out” deal, which returned around 1,500 small boat migrants to France and accepted around 1,500 asylum seekers with links to Britain.
Despite the data showing the UK’s ability to remove migrants remained limited as an EU member, Mr Burnham opted to borrow Sir Keir Starmer’s Brexit-bashing assessment in his first conference speech as Labour leader.
The Prime Minister also used his Brexit warning to point out the UK no longer has access to the EU’s migration data-sharing processes.
Eurodac, to which the UK had full access before leaving the EU, stores the fingerprints of asylum seekers and certain irregular migrants, allowing authorities to identify previous asylum applications in other member states.