The courts would almost certainly rule against any attempt by MPs to use the Parliament Acts to pass legislation which would indefinitely delay a general election, according to an important new judgement.

And the Court of Appeal also indicated on Wednesday that the Commons could not pass legislation to abolish the upper chamber unless the peers themselves consented to the move.

However, the judges stopped short of making this a definitive ruling, saying that future cases based around such events would have to be considered on their merits.

The findings are the result of a legal bid to overturn the controversial ban on hunting, which was passed using the 1949 Parliament Act having failed to gain the support of the House of Lords.

In essence, the 1949 law allowed legislation to reach the statute book despite rejection by the Lords, although peers retained the ability to delay it by one year.

However, the 1911 Parliament Act - which established delaying powers of two years - was relied upon to enact the 1949 legislation.

Members of the Countryside Alliance sought to have the hunting ban ruled unlawful on the grounds that the 1949 legislation was itself improperly passed using the 1911 Act.

Although the alliance failed in its challenge, the case raised a series of important constitutional issues and was heard by Lord Justice May, Master of the Rolls Lord Phillips and Lord Chief Justice Lord Woolf.

Jurisdiction

One key issue that was settled in the judgement was whether the courts could rule on whether legislation that had received Royal Assent was in fact valid.

The court said it was an "unusual, and in modern times probably unprecedented" decision to make.

The attorney general was said to have presented "no convincing answer" about why the courts should have jurisdiction, but the judges said that the determination of questions of interpretation and ascertaining the effect of legislation "is part of the normal diet of the courts".

"The circumstances in which it will be appropriate for the courts to become involved in issues of this nature are limited, but in this case it is perfectly appropriate for the courts to be involved," said the ruling.

"If the courts did not adjudicate on the issue, there would be great uncertainty as to the legal situation, which could have most unfortunate consequences after 19 February 2005, when the Hunting Act is meant to come into force.

"In exercising this role, the administrative court and this court on appeal are seeking to assist parliament and the public by clarifying the legal position when such clarification is obviously necessary."

Legislation issue

The attorney general had defended the anti-hunting legislation on the ground that any bill passed in accordance with the 1911 Act, as amended in 1949, had the same status as a bill passed in the normal way with the consent of both houses of parliament.

Lawyers for two members of the Countryside Alliance, however, had claimed that legislation passed in the normal way was not reliant on a separate piece of legislation, and was therefore in a separate class.

The Court of Appeal said it was "undoubtedly correct" to say there are two classes of legislation - that passed with the consent of both houses and that passed by the Commons using the Parliament Acts.

The judgement said they backed the view that there are two classes because otherwise "the 1911 Act could be used to extend the life of parliament" contrary to the express language of section two of the 1911 Act.

That section makes it clear that the original Parliament Act cannot be used for "a money bill or a bill containing any provision to extend the maximum duration of parliament beyond five years".

"All that would be required would be for parliament, in the shape of the Commons, to pass legislation deleting the words 'bill containing any provision to extend the maximum duration of parliament beyond five years' and then to pass further legislation extending the life of parliament," said the judges.

"This would be quite contrary to the express limitation on extending the duration of parliament contained in s.2(1) and we are not prepared to accept that this is the position."

The judges added: "We appreciate that it is most unlikely that the Commons would ever contemplate seeking to use the 1911 Act, either in its amended or unamended form, to enact legislation to which the House of Lords had not consented, in order to extend the duration of parliament or, for that matter, to abolish the House of Lords.

"However, if, contrary to our expectations, it did contemplate such action we would regard this as being contrary to the intention of parliament when enacting the 1911 Act."

Constitutional settlement

The ruling also said that the preamble to the original Parliament Act "provides no support for an intention that the 1911 Act should be used, directly or indirectly, to enable more fundamental constitutional changes to be achieved than had been achieved already".

"Thus, it does not necessarily follow that because there is compliance with the requirements in the 1911 Act, the result is a valid act of parliament," said the judges.

And they warned MPs that if the Commons "attempted to extend the life of parliament in excess of five years without the consent of the Lords the attempt would be ineffective and, if necessary, the court's jurisdiction that we are now exercising could be invoked".

"With the consent of the Lords and Commons, parliament could extend the life of parliament for say two years without having to amend the 1911 Act.

"Indeed, it did so during the Second World War. (We deliberately confine the extension for a limited period because there could be different arguments if parliament attempted to extend its life indefinitely)."

Parliamentary behaviour

The Court of Appeal said that while the 1949 Act might be lawful legislation, it did not follow that "the 1911 Act can be used or amended, so as to produce results that will constitute a different constitutional settlement".

As a result, the case hinged on whether the 1949 Act made significant changes to the constitutional position.

In reducing the Lords' delaying powers from two years to one, the court ruled that the threshold of major change had not been crossed.

Such a change in the previous position was "relatively modest", they said.

In addition, parliament itself had not given any indication that the 1949 Act was disputed, with both houses having previously amended legislation originally passed using the Act.

"The manner in which both houses have acted, with the assent of the monarch, from 1911 up to the present day, demonstrates a consistent approach to the nature of the change made to the constitution by the 1911 Act," said the ruling.

"We have concluded that this, of itself, is a most material factor in deciding whether the Hunting Act is a valid act of parliament."

Key ruling

The judges said that "there was power to amend the 1911 Act to the extent of the amendment contained in the 1949 Act".

"We have not been prepared to go further than that," they added.

"However, accepting a power of amendment of this nature exists is quite different to allowing the power of amendment to extend to making changes of a fundamentally different nature to the relationship between the House of Lords and the Commons from those which the 1911 Act had made.

"The 1949 Act left the relationship between the House of Lords and the House of Commons substantially the same as it was before the 1949 Act. It reduced the length of the period for which the House of Lords could delay legislation proposed by the Commons.

"What, if any, further power of amending the 1911 Act that Act authorises should not be determined in advance of an attempt to make a more significant amendment than that contained in the 1949 Act.

"It is, however, obvious that on our approach, the greater the scale of the constitutional change proposed by any amendment, the more likely it is that it will fall outside the powers contained in the 1911 Act.

"Our decision is limited to indicating that if what is involved is properly described as a modification of the 1911 Act it is legally effective."

The Countryside Alliance said it would appeal the decision to the House of Lords.