From time to time, the mechanics of Parliament come under scrutiny and cause confusion. One possible reasons for this is that Parliament has been making its rules for around 800 years. The way the rules work is not always in a manner that makes sense in a modern world. Much of the way we do business in parliament is done by conventions and traditions.
The row over the changes to tax credits has thrown the conventions of parliament into a harsh light - especially the role of the House of Lords.
Over the years, I have received many letters from local residents worried that an unelected House of Lords can decide on how we lead our lives and what laws govern. My view has always been that as a 'revising chamber' the House of Lords does an important job. Those who are asked to go to the Lords are usually people who have made an outstanding contribution to their field of expertise and bring a wealth of knowledge to the law making process. They will pick up minute details in laws made in the House of Commons that we miss and their skill lies in advising a better solution than the one we came up with.
But for this to work, and for people to accept - even grudgingly - that the Lords has a place, they must stick to conventions. There are two incredibly important conventions that they must observe.
The first is to never reject a policy that is a manifesto pledge of an elected government - the country has spoken and they must never contradict the democratic mandate of the government. The second is that the government must be allowed to run the country's finances as it sees fit.
The intervention by the Lords this week to reject the government's policy on tax credits breaks both these conventions. £12 billion of cuts to welfare was a manifesto pledge, and the £4 billion saved by cutting working tax credits is a fiscal decision by the government. Irrespective of people's views on the policy, the intervention by the Lords is wholly wrong and raises some very significant constitutional problems.
I am aware that for many, this policy is not popular, but should the Lords do this again, they could easily do it on a policy that is not so unpopular. That is why this issue needs resolving and resolving fast.