What mechanisms exist to prevent "hard" Brexit?

Question

I'm looking for legal and constitutional mechanisms that could prevent a hard Brexit, e.g. by keeping us in the Common Market. For example, could the Lords delay the triggering of Article 50 indefinitely? Or could the parliamentary vote result in a vote of no confidence in the government and subsequent election? More generally, how does one stop a British prime minister from making a bad decision?

The Prime Minister, Theresa May stated on 17/01/2017 that she wants a "hard" Brexit, including the UK leaving the single market and generally making a complete break with the EU.

What, if any, ways could this be stopped? By stopped I mean significantly softened or leaving the EU cancelled entirely. Failure to get the deal May wants and falling back to WTO rules would also be considered a "hard" Brexit in this context.

Answer 1

The House of Lords is a revising chamber, it can not prevent the commons from passing laws but it can use its powers to delay their passage. They can amend laws that come before them and send those changes back to the Commons who can vote to include them or vote to reject these changes and send it back to the Lords and ask them again to vote in favour of the legislation as the Commons have structured it. I understand that this parliamentary ping-pong, as it is known, can last for a maximum of three years. Not long enough to prevent passage during this fixed term or 5 years.

Also the Commons can use the powers invested in the lower chamber by the Parliament Act of 1911 to override the Lords by a majority vote of MPs in favour of such a move and then send the bill directly to the Queen for Royal Ascent. Whereupon it becomes an Act of parliament and is now law. This was how Tony Blair got his anti-foxhunting bill passed.

There is a tradition called the Salisbury Convention whereby the Lords should not obstruct measures which are manifesto commitments of the elected government of the day. The Conservative manifesto promised to have a referendum on membership of the EU and to abide by the result as the decision of the British people.

If the Lords did attempt to obstruct the will of HM Government and/or the Commons, it could well be the case that they would be signing their own death warrant as a non-elected chamber.

All political commentators are sure that Article 50 will be triggered by the end of March if not before. Anyone who doesn't want this to happen will be disappointed.