I still think that we did the right thing to go into Government. We did a lot of good on mental health, the environment and education and we stopped the Tories from doing a whole load of nasty stuff that they proceeded to do the minute we were out the door.

However, we made some howlers of mistakes. It would be very strange if we didn’t. Some of them were completely avoidable. And one in particular, I can’t just let pass.

Recently, Polly Mackenzie, then a Special Adviser to Nick Clegg, was celebrating the Lib Dem plastic bag tax.

Four years ago Lib Dem Ministers started agitating for a 5p charge on plastic bags. It took us months to persuade Cameron and Osborne. — Polly Mackenzie (@pollymackenzie) April 19, 2018

But this admission made many of us choke on our tea.

We finally got the policy in an eve-of-conference trade, in return for tightening benefit sanctions. — Polly Mackenzie (@pollymackenzie) April 19, 2018

Come again – you mean, the sanctions regime that forces people to food banks, that leaves them without the basic means of providing for themselves – we agreed to that in order to get a plastic bag tax?

But it was ok, because…

PS the benefit sanction turned out to be illegal and never went ahead. Ha Ha. — Polly Mackenzie (@pollymackenzie) April 19, 2018

No. This was not ok. Sanctions were implemented and tightened by the Coalition Government and caused untold hardship. Our MPs voted for it. The fact that such a brutal policy was traded in such a blasé fashion probably isn’t news either. It shouldn’t happen again though.

There are two lessons which must be learned from all of this.

The first is that before we agree to anything, we need to check whether it conflicts with the Preamble to our Constitution. Now, the plastic bag tax definitely fits to our values around “responsible stewardship of the earth’s resources.” However, in no universe could increasing the hardship faced by the most vulnerable people in our society ever be in tune with “none shall be enslaved by poverty, ignorance or conformity.” That should have bounced that proposal off the park immediately.

The second is that we should have a proper understanding of the effect on people of any policy we implement. I don’t think for a moment that anyone doing those deals actually thought about what this would actually involve in practice. That for spurious reasons people could be brought to the brink of homelessness and starvation. I doubt anyone involved had any idea what it was like to be in this position. We must always have in our mind how our policies are going to impact on people’s lives and if we don’t know, we should ask the expert organisations who support people in poverty.

And it would be helpful if those involved in making such deals didn’t boast about them on Twitter. It really, really doesn’t help.

* Caron Lindsay is Editor of Liberal Democrat Voice and blogs at Caron's Musings