Your editorial (Humans must not become back-seat drivers for computers, 2 July) reaches the right conclusions that cars will be safer when humans no longer drive, but there is much more to it than recognising large white articulated trucks, paper bags or aggressive drivers.
With Merkel looking on, Varadkar vowed that Ireland would not become a "back door" for third-country goods into the EU but ducked a question about where Ireland would impose checks if not on the border.
Millions have already been spent on building bigger fences at Calais to ensure that the port does not become a back door, or indeed a front door, for illegal entrants into Britain.
"We are concerned about the possibility of groups like the Islamic State of Iraq and Syria (ISIS) exploiting the refugee resettlement process to set up operatives in the West," they wrote, adding "we want to make sure the Syrian refugee program does not become a back door for jihadists".
Chris Ham, head of the influential King's Fund think-tank, says resorting to such measures should be a "last resort and must not become a back-door route" to change.
It also clearly wants to signal that the wishes of a member country will always take priority over those that decide to spurn the union and to preserve the integrity of its common market, so that a porous Irish border doesn't become a back door for smugglers.
Now sensitized to a negative outcome, parents tended to hold back and not become as emotionally involved in a subsequent pregnancy.
Do not become clingy if he's backing off.
"Vienna should not become Chicago" was a favorite slogan back in the 1990s.
Because the war was in its early days and the partisan war in the southern back country had not become as brutal as it would be later in the war, the siege was conducted desultorily, and was effectively a stalemate.
Do not become weary in well doing nor fall back.
