The Hunting Bill is entering what could be its final week of parliamentary debate. Here's a guide to what happens now.
The hunting bill is entering its final stages
What does the Hunting with Dogs Bill do?
In the version MPs want, it would ban all hunting with dogs. A person "commits an offence if he hunts a wild mammal with a dog, unless his hunting is exempt".
Originally, a bill introduced by the government last year proposed banning stag hunting and hare coursing, but would have allowed some fox hunting to continue under licence.
This was a compromise which ministers hoped would get the backing of both the generally anti-hunting Commons and the generally pro-hunting Lords.
So why hasn't it become law?
Anti-hunting MPs last year voted for the government's compromise bill to be re-written to become a wholesale ban on hunting with dogs in England and Wales.
The House of Lords then rejected that call in a vote in October 2003.
That led to deadlock and so the bill was killed off during that session of Parliament.
So what is happening this week?
The bill, outlawing all hunting with dogs, has been re-introduced with identical wording, which means the rarely used Parliament Act can be used to force it through even if the Lords oppose it.
The Hunting with Dogs Bill was reintroduced in September with MPs heavily backing a ban in a free vote.
The House of Lords has voted to replace an outright ban with a licensing system, similar to the government's original plan.
The Parliament Act?
The House of Lords is meant to revise and, if necessary delay, House of Commons plans it does not agree with. The idea is that some compromise is reached.
However, if there is steadfast disagreement between peers and MPs, such as over hunting, the Parliament Act can eventually be used to force a Commons-backed measure into law despite the opposition of the Lords.
It is a major step to take - one which has only been taken three times since 1949 - on the War Crimes Act 1991, on proportional representation in European Parliament elections in 1999 and in 2000 for lowering the age of consent for homosexuals to 16.
How would it work in this case?
The Parliament Act could only be invoked if peers voted to block the bill for a second time.
If the Lords voted the bill down, it would still become law by the end of the session (i.e. November), providing the Commons Speaker certifies that the provisions of the Parliament Act have been complied with.
How close are we now to a ban going through?
If there is no deal struck between MPs and peers, an outright ban is likely to become law by the end of the week - when this session of Parliament ends.
The House of Lords votes on Monday on giving the now heavily-changed bill a third reading.
It then returns to the Commons on Tuesday, when MPs are expected again to insist on a complete ban.
This ping-pong could continue until the two Houses of Parliament rise on Thursday. As long as the speaker certifies it meets the Parliament Act conditions, it would then just await the formality of royal assent before entering the statute books.
And when would it come into force?
Peers have voted for hunting to continue unrestricted until at least the end of November 2007.
They have yet to consider the MPs' suggested amendment of delaying a ban for 18 months to give hunts time to re-house dogs and to allow businesses to "refocus" their work.
If the Lords reject that idea and a ban is pushed through, it could come into force three months later.
Some peers want to do just that to make ministers deal with enforcing a ban before the next general election.
Ministers do, however, decide when new laws become live and they could use those powers to bring a delay without any reference to Parliament.