How does the Benn Act prevent a No-Deal Brexit?

David Miliband:

What is the Benn Act and how does it prevent no-deal Brexit?

The Benn Act is named after Hilary Benn, a backbench Labour Member of Parliament, who rallied a parliamentary majority to defeat the government and insists that if the government has not negotiated a deal with the European Union on the three issues: of Northern Ireland, of citizens' rights, and of financial contributions by the 19th of October, then the prime minister is required to write to the European Union requiring or requesting an extension of the Brexit negotiating process from the 31st of October for three months. So, it ensures, this apparently watertight piece of legislation, that the government cannot lead the UK to crash out of the European Union with no deal at all.

Lord William Hague:

What is the Benn Act and how does it prevent a no-deal Brexit?

It is a law specially passed to force Boris Johnson to do what he doesn't want to do, to write a letter on October 19th if he hasn't made a deal with the EU, asking for a delay to Brexit. And it is very specific. It's the actual letter, written out word for word, with every full stop. He can't even put: "Why don't you all get lost" in the middle of it. Because that would be unlawful.