The House of Lords decides to obstruct a major Bill
When introducing a bill to Parliament there is always a chance that the proposals set out in the bill go against what the unelected House of Lords (the Lords) believes in, and therefore decides to veto. In these situations the House of Commons (the Commons) believes that it, the elected house, should prevail, and this view is supported by the Parliament Acts and the Salisbury Convention.
The Houses of Parliament in the UK is made up of the House of Commons, which is the directly elected house, where the Prime Minister, government and Members of Parliament (MPs) sit. The so called Upper House is the House of Lords which is made up of members known as peers. There are different types of peer with Life Peers being the most numerous since 1999, when hereditary peers were removed from the Lords almost entirely.  The appointment of peers has been made by the House of Lords Appointment Commission, which appoints the non-party or cross-bench members, they also vet the recommendations put forwards by the political parties yet it is the Prime Minister (PM) who appoints theses peers. Although not part of the Houses of Parliament, the assent of the monarch is required for a bill to become law, the power to grant assent on behalf of the Queen is carried out by a Lord Commissioner or in some cases by a Letter Patent.
The passage of a bill through Parliament is a fairly straight forwards procedure. Firstly a Bill is presented to the House of Commons at what is known as the First Reading, this is followed by the second reading where the Commons then debate on the proposals, if the bill survives this stage then then it moves to the committee stage. Here the bill is studied in great detail, any amendments suggested are considered in depth. After this stage the bill then moves to the Report stage, where the amendments made by the committee stage are discussed by the Commons. The Third reading follows when the bill is discussed in its entirety. If it’s then accepted the Bill moves to the House of Lords where the Bill goes through the same stages and if no amendments are made by the Lords then the Bill is sent for Royal Assent, when it becomes law. Any amendments by the Lords have to then be sent back to the Commons to be discussed again. This procedure can also happen in reverse, with the Lords introducing a bill, thought they are not as common.
Since the 1500’s an unwritten convention has been in place, which stated that the House of Lords wouldn’t veto a finance bill. This developed over time as the Commons gained more power and became more democratic and thus didn’t want the Lords to hold more power than the elected house. This stood until 1911 when the first Parliament Act was passed, despite harsh opposition by the Lords. This Act came about as the Lords blocked a controversial finance bill put forwards by the Commons and thus sparked a major constitutional crisis. This was resolved by Prime Minister Asquith (Liberal), who requested that the King create enough Liberal Peers (in order to outnumber the conservative peers who held a massive majority), if they didn’t agree to pass the bill. The Lords gave way and the bill was passed by 131 to 114 votes.
Prior to this, if one house vetoed a bill, then apart from making compromises, there was nothing that the House concerned could do to get the bill enacted.
The Parliament Act 1911 officially limits the powers of the House of Lords. Section (s) 1(1) states that the Lords can’t hold up a finance bill for any longer than one month, if the House of Lords do try to hold a bill for longer, then this section allows for the speaker of the Commons to present the bill to the monarch for Royal Assent. Therefore, under these conditions the government would be able to get the bill enacted, despite the opposition from the Lords.
The Parliament Act 1911 also provides for the provisions should the Lords block a non-finance public bill. S.2 (1) states that if the Commons pass a bill “in three successive sessions" and it’s rejected by the Lords, then after the Lords block it for a third time, the Speaker of the Commons is then able to send the bill to the monarch for Royal Assent, without the Lords consent. When assent is granted, then like finance bills, they are considered primary legislation. In all there must be a full two years between the bill’s second reading in the Commons and the second rejection of the Lords, for this bill to be then enacted by the monarch.
As well as limiting the powers of the House of Lords, the Parliament Act 1911 also limits the maximum length of a Parliament to five years, maintains the powers of the House of Commons and maintains the veto of the Lords when it concerns Provisional Order Bills and bills aiming to increase the life of a Parliament from five years.
This Act managed to work well for a number of years until the Commons feared the Lords would block a bill regarding the nationalisation of the iron and steel industries, despite the Lords agreeing to all the other bills of nationalisation put forwards by the government. As the government of the day didn’t have long enough in power to enforce the two year waiting period of the Parliament Act 1911, they introduce the Parliament Bill (soon to be the Parliament Act 19494) into the Commons. This was introduced because the Labour Government of the day didn’t want the House of Lords to “thwart the will of the people". Therefore, Asquith’s government decided to bring the Parliament Bill to the Commons which would further reform the veto powers of the House of Lords.
However, the Lords rejected this on the basis that it did not pose any serious reform of the Lords and that there was no public support of this bill, as there was for the Parliament Act 1911. Despite this, the Parliament Act 1949 was passed by using the conditions set out in the Parliament Act 1911.
This second Parliament Act (1949) set out a few amendments to the first Parliament Act. Instead of the Lords delaying Acts for two years, this second Act reduced it to just one year. Again, this is from the first, second reading in the Commons, to the second rejection by the Lords.
However, the Parliament Act 1949 has been criticised by many eminent academics as not providing primary legislation, but in fact of passing only delegated legislation. One such academic is Sir William Wade, who said that this second Parliament Act owes its validity to the first, which is the hallmark of delegated legislation. He claims that only Acts passed by the Queen in Parliament (the Commons, Lords and Assent) can be regarded as sovereign and primary legislation, therefore any Act passed by the Parliament Act 1949 is not in effect primary legislation.
However, this issue was resolved in the R (Jackson & Others) v Attorney General  where the House of Lords, in its judicial capacity, ruled that acts passed using the conditions set out in the Parliament Act 1949 were in fact valid and primary legislation. Nonetheless, the debate does still continue amongst academics.
In addition to these legal methods of avoiding the Lords consent, there is or was a convention that used to ensure the Lords didn’t necessarily have to agree with a bill for it to be passed into law. Around 1946, the primarily Conservative House of Lords decided that they would not obstruct a bill that was in the government’s manifesto when they were elected. This became known as the Salisbury Convention, after the peer who first proposed this set up. This convention would then allow the Commons to pass laws, provided they were in the manifesto, without the consent of the Lords.
However, there are many arguments about whether or not this convention still applies, since the House of Lords Act 1999, which removed all but 92 hereditary peers, the Lords have said that the convention only applied when there was a huge Conservative majority in the Lords. They claim that as there is no longer a strong majority and that it is more representative, there is no reason that it should still apply.
Contrary to this, is the argument from members of both Houses that the convention is not about the composition of the houses but the constitutional position of them. Baroness Jay of Paddington, the then Leader of the Lords, and a Labour peer, said in 1999 that:
“The Salisbury/Addison convention has nothing to do with the strength of the parties in either House of Parliament and everything to do with the relationship between the two Houses . . . It must remain the case that it would be constitutionally wrong, when the country has expressed its view, for this House to oppose proposals that have been definitely put before the electorate." 
A Royal Commission was also set up to investigate any further reform of the House of Lords, and in its report they expressively mentioned that the Salisbury convention should be maintained as its reasons were still “valid". A joint committee also set up for the same reason also found in favour of the Salisbury conventions stating that it maintains the “over-all effectiveness of Parliament"  . So, having said this it would suggest that the Salisbury convention is still in force.
In conclusion, it’s clear to see that the legal measures of the two Parliament Acts together with the Salisbury convention, do allow the Commons to push a bill through Parliament, without the consent of the Lords. Therefore, the government would be advised to rely primarily on the Parliament Acts as these (although they may throw up questions relating to their validity), are a much more certain way of ensuring the bill gets passed.
A.W. Bradley and Ewing, Constitutional and Administrative Law, (15th) 2010
O. Phillips & Jackson: Constitutional and Administrative Law (8th) 2001